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DEFICIENCY ANALYSIS OF THE TIP OF CHROMOSOME 3R IN DROSOPHILA MELANOGASTER

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Copyright 0 1986 by the Genetics Society of America

DEFICIENCY ANALYSIS OF THE T I P OF CHROMOSOME

3 R I N DROSOPHILA MELANOGASTER

KRITAYA KONGSUWAN, ROBERT P. DELLAVALLE AND JOHN R. MERRIAM

Department of Biology, University of California at Los Angeles, Los Angeles, California 90024

Manuscript received July 3 1, 1985 Revised copy accepted November 15, 1985

ABSTRACT

Region 98EF-100F in chromosome ? is interesting for genetic analysis because it contains a number of genes of developmental importance. Although there a r e n o preexisting simple deficiency stocks, this region is amenable to genetic ma- nipulation using other types of rearrangements. In the present investigation we obtained deficiencies by combining the terminal deficiencies formed by segre- gation of Y;? translocations with a series of duplications of the tip of ?R, both from Y;? translocations with different breakpoints and from ?;l duplications in which the 3R tip is carried as a second a r m on the X chromosome. Analysis of such synthetic deficiencies reveals five haplo-abnormal loci in the 98A- 1 OOF interval. T h e s e include a haplolethal site, a newly described Minute a n d three previously reported Minute mutations. T h e newly discovered Minute has been designated M(3)99D a n d is localized cytologically to bands 99D1-9. T h e three previously reported Minute loci in the region have been localized more precisely: M(?)1 to bands 99B5-9, M(?yto bands 99E4-Fl and M(?)g to region 100C-F. In addition, we have been able to obtain synthetic deficiencies uncovering all of the intervals from 99B5 to 100B. These deficiencies will be useful for future genetic and molecular analyses of the genes that map within the right tip of chromosome 3.

I T H recent advances in molecular genetics, an appreciable number of genes for which no function has yet been established have been cloned on the basis of their molecular properties

(6

MERRIAM 1985). One example is the 8 kb serendipity (sry) gene region, at 99D4-8. This region is molecularly and developmentally interesting because it encodes two blastoderm-specific transcripts and at least two other mRNAs which are expressed during both oogenesis and embryogenesis (VINCENT et al. 1984; VINCENT, COLOT and Ros-

BASH 1985; LENGYEL et al. 1985; ROARK et al. 1985).

We are interested in determining the function(s) of the sry region by isolating mutations in the genes. Mutations per se are simple to isolate; the difficulty lies in getting mutations in the desired regions and knowing it. T h e problems both of isolating mutations in the vicinity and of identifying those potentially defective in the functions of interest are eased if deficiencies for segments of the region can be used (e.g., JUDD, SHEN and KAUFMAN 1972). Unfortunately, such deficiencies were not already extant for the 99D interval. In a previous

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540 K . KONGSUWAN, R. P. DELLAVALLE AND J. R. MERRIAM

study, LINDSLEY et al. (1972) found that the relatively large segmental hypo- ploid for 99B to 99F is haplo-inviable and suggested that both their results, and the lack of simple deficiencies in the region, may be due to a number of

Minute genes previously shown to be in this region by recombination mapping

(LINDSLEY and GRELL 1968). They noted that, in general, lethality associated with large deficiencies can be eliminated by dividing the interval into smaller deficiencies. Hence, using more closely spaced breakpoints, we hope to obtain smaller deficiencies in the 99B to 99F region for which heterozygotes survive. I n addition, we could also expect to position the known Minute genes in the region more exactly.

Our solution to the problem of obtaining deficiencies of 99D and the sur- rounding interval from 98EF to lOOB has been to carry out the segmental aneuploidy procedure with T(K3)'s and 3;l duplications. The latter were ob- tained from FRISARDI and MACINTYRE (1984) and contain the right tip of the third chromosome extending distally from breakpoints between 99B and 1 OOB.

Evidence is presented for the localization of three previously reported Minute

loci at 99B5-9, 99E4-Fl and 100C-F and for an additional Minute locus that maps at 99D1-9. This last Minute gene has been shown by us (KONGSUWAN et

al. 1985) to code for ribosomal protein 49. T h e relative order of rearrange- ment breakpoints has also been confirmed or established by genetic and cyto- logical criteria.

MATERIALS AND METHODS

Stocks: T h e stocks used to generate segmental aneuploids are listed in Table 1 . These are as follows:

1. T h e Y;? translocations as described by LINDSLEY et al. (1972) and the SEATTLE- LA JOLLA report ( 1 97 1 ) were used, in which the third chromosome is either reciprocally interchanged with o r partially inserted with the Y chromosome. T h e translocated Y chromosomes were originally marked with the normal allele of yellow

01')

in the short arm ( Y S ) and with Bar (Bar of Stone-B") in the long arm ( Y L ) . All translocations except B226 and Rl?? have lost the B" marker

. T h e third chromosome balancer is

Zn(3LR) T M 6 , s s - b ~ ~ ~ " U b x ~ ' ~ e , and the sex chromosomes are attached-X in females and attached- XY in males; both are marked with y . Some translocation stocks carry TM6 without the Ubx marker.

2. T h e ?;l duplications, kindly supplied by FRISARDI and MACINTYRE (1984), are terminal portions of the right tip of chromosome 3. T h e original line, Dp(3;1)B152, was formed by appending the terminal portion of the E? translocation, B152, to the right arm of the X chromosome (KANKEL and HALL 1976). This duplication bears ca+ and bu+. All other duplications listed in Table 1 (e.g., Dp(3;1)46A) were c a - ( b v + ) deficiencies X-ray-induced on Dp(?;I)BI52. Hence, each duplication obtained by FRISARDI and MA- CINTYRE contains two breakpoints: one to the left of the ca locus, usually in the het- erochromatin (H) between the duplication and the centromere [ X R or the segment of YL transferred from the original T(E3)], and one distal to ca but proximal to bu. This latter breakpoint marks for us the proximal extent of the terminal duplication. FRISARDI and MACINTYRE in fact referred to their constructions as ca deficiencies, but we refer to them instead as, more simply, duplications. These ?;I duplications are maintained in stock as 443; I)-bearing males homozygous for ca and bu crossed to C ( I ) D X / Y females also homozygous for ca and bv (FRISARDI and MACINTYRE 1984).

Third-chromosome balancers used are Zn(?LR)TM6, s s - b ~ ~ ~ ~ UbP7'e; In(?LR)TM3, ri

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ANALYSIS OF THE TIP OF 3 R

TABLE 1

A list of the Y;3 translocations and 3:1 duplications used to generate synthetic deficiencies and their salivary chromosome cytology

54 1

Markers YITMC Brea kooin ts" Stock

T(y;?)J55 (1ns)b y+/Ubx 98A; lOOB

T( Y;?)8226 (YL) y+B' 98EF'

T(Y;?)B8J (YL) y+/Ubx 99D 1 -2d

T(Y;?)G116 (YL) y+/Ubx 99E4-F1, complex

T(Y;?)P60 (YL) Y + 99F

T(Y;?)A1J? (YS) y+/Ubx 100Ad

Of(?; J)BJ52 XR; YL; 98F14

T(Y;?)LJ27 y+/Ubx 99B5-6; 99E4-Fl

T(Y;?)RJ?? (YL) y+B*/Ubx 99D9-E5

T(Y;?)LJ29 (YS) y+/Ubx 1 OOC

Derivatives of Dp(?; J)BJ52

Dp(?; 1)46A H; 99B5-9

Dp(?; 1)74 H; 99C2-6

Dp(?;1)27 99B4-5; 99BlO-Cl

OF(?; J)78 H; 99C5-7

Dp(;t; l) R 14 99A8-9; 99D1-2'

Dp(?;l)RJO H; 99D6-9'

Dp(3; J)67A H; 99D9-Eld

Dp(?; 1)?4 H; 99E5-Fl

DPO; J)? H; 99E5-Fl

Dp(?; J)88 H; 99F6-8

Dp(3; 1)9? H; 99F9-10

Dp(?; J)I52P H; 100A1-2*

Dp(?; 1 ) J50P H; 100B1-2d

Dp(?;1)79 H; 100B4-5'

Dp(3; J)1A H; 100B5-71

Dp(?; 1)48 H; 100B7-Sd, complex

H refers to a heterochromatic breakpoint. For translocation stocks, the following information is given: (1) whether the Y chromosome breakpoint is in the long arm (YL) or the short arm ( Y S ) ,

(2) markers remaining on the T(Y;?) chromosome and (3) whether the balancer chromosome Jn(?LR)TM6 carries the Ubx marker.

a T h e T(Y;?) salivary chromosome breakpoints are those listed by LINDSLEY et al. (1972) and by

the SEATTLE-LA JOLLA Drosophila Laboratories Report (1971); the duplications are those of FRI- SARDI and MACINTYRE (1984), except where noted.

Dp(3; J)67N H; 99D6-9'

Dp(3; J ) J24P 99A2-3; 99E4-5

Insertional translocation.

Confirmed by the authors.

' S. FALKENTHAL (personal communication); previously placed at 98B.

'-1 Changed by the authors. e Previously placed at 99C7-8; 'previously placed at 99D2-5; 8 pre- viously placed at 99D9-El; T. STRECKER (personal communication)-previously placed at 99F7- 8; ' T. STRECKER (personal communication)-previously placed at 99F2-6; T. STRECKER (personal communication)-previously placed at 99F9-100Al.

as T M 6 , TI43 and In(3R)C, respectively. For descriptions of visible mutations, with the exception of T6, see LINDSLEY and GRELL (1968); for Tb, see CRAYMER (1980).

All crosses were performed at 25 O

.

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542 K . KONGSUWAN, R . P. DELLAVALLE AND J. R . MERRIAM

3

4

X TM6 Inf3RIC bb

Dpf3; JI Df f3R/

$ $ Dpf3; I/ Dff3R;

x

-;

-

[OfT]

x?

I ~3 YA

+

x

-.

Dpf3. JI Dff3Rj

$' -.

X ' TM6 [or /nf3R/C]

,

Y ' TM6 [or Inf3RIq

+

Stock

FIGURE 1 .--Crosses used to obtain segmental deficiency stocks from D p ( 3 ; I ) s . Genotypes pro- duced by this mating are shown in Figure 2, and progeny numbers from this cross are tabulated in Table 3 .

niosome balancers. To maintain M i n u t e deficiency stocks, we constructed a chromosome carrying a duplication of region 99 (to cover the Minutes) and a rearrangement (to suppress crossing over). This was achieved through recombination between two inver- sion-bearing chromosomes, kindly supplied by E. B. LEWIS, for which the right-hand break- points flank the 99 region: Z n ( 3 R ) M c p ' " 3 ' 5 , broken at 89E and 98D-F, and I ~ ( ~ R ) U ~ X ' ~ ~ * ~ I f i N , broken at 89E and 99F. A recombinant (referred to as

I n ( 3 R ) U b d M c p R ) was obtained that bears the left breakpoint of the Ubx inversion (and is marked with U b x ) and the right breakpoint of the Mcp" inversion. Flies bearing the M i n u t e deficiencies M ( 3 ) I , M ( 3 ) 9 9 D and M(32f (described below) i n trans with this chro- mosome are M+ and Ubx in phenotype.

Constructing segmental deficiencies from crosses between different T(y;3)s: The technique of segmental aneuploidy (LINDSLEY et al. 1972) was used to generate a series of overlapping deficiencies of approximately one lettered subunit or larger spanning region 98A-1 OOC. Deficiencies constructed in this manner may exhibit the marker phenotypes y+ or y+B5, y or yBS and Ubx+ or Ubx, depending on (1) the location of the breakpoint in the Y chromosome, (2) the markers present in the translocated Y chromosome and (3) the presence or absence of the Ubx marker on the TM6 chromo- some. We were able, in all cases, to distinguish the deficiency-bearing class from other classes of progeny by means of these marker phenotypes.

Constructing segmental deficiencies from crosses between the T m 3 ) and the 3R tip duplications: Small deficiencies were constructed by combining the deficiency formed by segregation of a Y;3 translocation with the appropriate duplication through the series of crosses outlined in Figure 1. Figure 2 diagrams a Punnett square example of the mating between duplication-bearing females and translocation males yielding segmentalzdeficiencies (cross 2, Figure 1). In Figure 2, daughters with the Sb, Ubx+ [ D p ( 3 ; I ) / X Y ; T M 3 / D f ( 3 R ) ] and wild type [ D p ( 3 ; I ) / s ; + / D f ( 3 R ) ] phenotypes are segmen- tal hypoploids. If these females survived, we judged the interval between the autosomal breakpoint of the T ( K 3 ) deficiency segregant and the breakpoint of the duplication could be made deficient in heterozygotes. If survivors displayed a Minute phenotype, then the interval uncovered by the combination between the T(Y;3) deficiency segregant and the duplication was associated with the Minute effect [Minutes are classically defined as dosage-sensitive loci (SCHULTZ 1929; LINDSLEY et al. 1972)]. T h e absence of both Sb, Ubx+ and wild-type females suggested that the region uncovered by the combination is haplo-inviable, i.e., presence in only one dose leads to lethality.

If the synthetic deficiency obtained in this manner did not exhibit a M i n u t e effect,

(5)

ANALYSIS OF THE TIP OF 3 R

543

I I I

--

Sb Ubx e Sb

OP Sb

- -

Sb Ubx e Sb

Sb

I

lethal

I

female

I

male

-

l’segmenta\l aneuploids

‘leu pl o id s”

Sb Ubx e male

Sb Ubx e male

__v__J

“terminal hyperploids

FIGURE 2.-Genotypes which are produced by the mating of Dp(jr;I)-bearing females with T(Y;?) males (second cross of Figure 1). T h e cross produces offspring which can be classified into three gIoups: segmental aneuploid females, “euploid” males and females and terminal hyperploid males.

Tb males (cross 3, Figure 1). Progeny receiving the synthetic deficiency and the paternal balancer chromosome were isolated and crossed inter se to form a balanced deficiency stock (cross 4, Figure 1). Minute females were crossed to Zn(3R)UbxLMcpR-bearing males in order to form balanced deficiency stocks.

T h e crosses described above were also repeated with longer duplications, the break- points of which were proximal to that of the T(Y;3) deficiency segregant. In this case, a small region of overlap duplication (rather than a small deficiency) is generated. It was anticipated that homozygotes for such small regions of overlap would be viable; consequently, the stock obtained from crosses between such duplication heterozygotes would yield adult progeny not carrying the balancer chromosome. This was used, as described in the RESULTS, to map the exact location of the translocation breakpoints with respect to the duplications.

T h e balanced deficiency stocks obtained by these methods are appropriate for use in crosses to uncover recessive mutants

U.

MERRIAM and T. STRECKER, unpublished re- sults). It should be noted that reciprocal outcrosses do not yield identical results, in that segregation of Dp(3;I)lY; TMGIDf(3R) males, for example, yield both TM6, Ubx and deficiency-bearing (non-Ubx) daughters, but only TM6, Ubx sons.

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544 K. KONGSUWAN, R. P. DELLAVALLE AND J. R. MERRIAM TABLE 2

Results of crossing males and females that carry different T(F3)’s

Crosses Df heterozygotes

Region made Total

Females Males deficient Normal Minute scored

8226 98.4-EF 0 0 2 3 2

881“ 98EF-99D 0 0 3 7 9

8226

8226 Rl?? 98EF-99E 0 0 517

88 1 R13? 99D-99E 0 108 4 2 9

Rl?? GI16 99E-99F 0 38 247

RI?? P60 99E-99F 0 18 3 0 4

RI?? A113 99E-1 OOA 0 6 0 4 3 2

R I 3 3 L129 99E-100C 0 4 171

GI16 A l l ? 99F-100A 2 9 0 168

GI16 L129 99F-100C 34 0 153

P60 A1 13 99F-1 OOA 8 0 0 2 8 2

P60 L129” 99F-100C 6 6 0 229

J55

T h e table is organized in the order of translocation breakpoints from proxi- mal (top) to distal (bottom), and only the crosses using the translocation with the more proximal third chromosome breakpoint as the maternal parent are shown; this produces deficiency-bearing progeny as females. T h e reciprocal crosses, in which the deficiency-bearing heterozygotes were males, gave equiva- lent results.

a Also studied by LINDSLEY et al. (1972)

RESULTS

T(Y;3) crosses: Table

2

presents the results of crosses between Y;? translo- cations with different third-chromosome breakpoints. T h e cross of J55 with B226 revealed that region 98A-EF is haplo-inviable. A similar result is obtained for region 98EF-99D because deficiency heterozygotes from the cross of B226 with B 8 1 do not survive. These results are, in general, similar to those of

LINDSLEY et al. (1972), who reported that the intervals 97F-98B and 98EF-

99C were haplo-inviable.

T w o Minute loci were identified by the crosses involving T(Y;?)RI??: one to the left of the R13? breakpoint (uncovered by the 8 8 1 X RI?? cross) and the other to the right (uncovered by the R13? X G116, RI?? X P 6 0 , RI?? X A113 and RI?? X L129 crosses). T h e 99C-F interval, where these Minutes are located, was tested in toto by LINDSLEY et al. (1972) (B81 X P 6 0 ) and was found to be haplo-inviable. It is entirely in keeping with their observations and overall conclusions that the lethality associated with the larger deficiency can be alle- viated by dividing the interval into two smaller deficiencies.

Deficiency heterozygotes for the 99F- 1 OOC interval are viable, fertile and not Minute. This is clear from the crosses G I 1 6 X A l l ? , G I 1 6 X L129, P60

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ANALYSIS OF THE TIP OF 3 R 545

it is likely that M ( 3 ) f corresponds to one of the two Minutes in the 99C-F interval mentioned above. Testing this deduction is not possible, because the original M ( 3 ) f stock has been lost (LINDSLEY and GRELL 1968).

Deficiencies from crosses between

3R

duplications and 8 3 translocations:

We combined each of the terminal deficiencies created by segregation of the available E 3 translocations with several of the shorter duplications (Table 1). With the exception of 99AB, we were able to recover deficiency-bearing flies for all sections of the 98EF-100B region.

Region 98EF-98F14: T o determine whether a deficiency of this region can be obtained, we combined the terminal deficiency generated by translocation

B226 with the longest duplication, B 1 5 2 , broken at 98F14. D p ( 3 ; 1 ) B 1 5 2 / X Zn(3R)C, Sb Tb/Df(3R)A113 females were mated to B226 males. B” Sb Tb (i.e., XY/Dp(3; I)B152; Zn(3R)C, S b Tb/Df(3R)B226) females were recovered (Df fe- males/total = 4/189) and did not display a Minute phenotype. We conclude that this region contains no haplo-abnormal loci.

Region 99BC: T h e insertional translocation L 127 has a proximal breakpoint at 98B5-6 (FRISARDI and MACINTYRE 1984). To uncover the interval distal to the breakpoint of this translocation, the deficiency segregant from L127 was combined with duplications 46A, 2 7 , 7 4 , 78, R 1 4 , RIO, 6 7 A and 3 (Table 3).

In all cases, heterozygotes of the genotype D p ( 3 ; 1 ) / X ; D f ( 3 R ) L 1 2 7 / + display a strong Minute phenotype and are sterile. Deficiency heterozygotes usually dis- play several Minute effects, including rough eyes and slightly plexate wings. T h e deficiency mapping and complementation analysis carried out by FRISARDI and MACINTYRE (1 984) showed that a Minute gene distal to the left-hand breakpoint of L127 corresponds to M ( 3 ) l and maps in 99B5-9. For this reason it is distinct from either of the Minutes described above in the R 1 3 3 crosses (Table 2). We note that the phenotype of the smallest deficiency heterozy- gotes-L 127-46A combination-is considerably more severe than that of the mutant M(3)l stock obtained from the Bowling Green stock center. It is pos- sible that the deficiency heterozygotes uncover both M ( 3 ) l and another more extreme Minute or, alternatively, that the mutant M ( 3 ) l is a hypomorphic allele.

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546 K . KONGSUWAN, R . P. DELLAVALLE AND J. R . MERRIAM TABLE 3

Progeny produced from cross 2 of Figure 1, in which females carrying duplications of the tip of 3R chromosome ( D p ( 3 ; 1 ) / x TM3, Sb/+) are crossed with Y;3

translocation-bearing males

n p y : I ) T W ) No. of segmental aneuploid" female progeny No. of No. of terminal wild Sb 3 euploid" hyperploid"

Fet11aIe5 Males Sb type Minute Minute progeny progeny

46A 46A 27 74 78 R I 4 RIO 6 7A 3 74 78 K14 RIO 6 7N 6 7'4 3 R I 4 6 7A 3 88 1501' 48

6 7h' 6 7A 1 2 4 P 3 xx IA 34 93 1521' 1501' 79 I A 48 I50P 48 8226 L127 L127 L127 L127 L127 L127 L127 L127 B8 I B8 I

B8 I

n8i

n8 I

ns

1

B8 I R I 3 3 K133 R I 3 3 R I 3 3 R133 R133 G I 16 G I I6 G I 1 6 G I 1 6 GI 16 GI I6 A l l 3 A113 A l l 3 A113 A113 A 1 1 3 A l l 3 L129 L129 0 0 0 0 0 0 0 0 0 20 13 21 0 0 0 0 8 18 0 0 0 0 1 1 23 21 1 1 6 3 23 14 21 32 27 8 42 22 24 0 0 0 0 0 0 0 0 0 34 25 40 0 0 0 0 25 17 0 0 0 0 29 32 39 18 30 18 27 27 27 63 30 24 80 33 30 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 3 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 23 26 24 12 19 13 18 6 0 0 0 40 5 40 7 0 0 8 1 2 34 40 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

114 28

464 128

462 134

517 109

429 134

694 142

518 74

527 176

625 224

181 38

142 37

267 51

42 1 74

129 20

539 108

462 134

99 23

1 i 5 17

124 26

92 21

416 129

538 108

202 62

163 32

156 39

86 14

135 36

139 28

174 41

182 46

173 55

46 1 170

152 62

119 31

475 127

37 1 106

35 1 130

As defined in Figure 2

Minute locus falling between the R 1 4 and RIO breakpoints (i.e., 9901-9). We name this previously undescribed Minute M(3)99D. It is clearly distinct from M ( 3 ) l because the 7 4 , 7 8 and R 1 4 duplications uncover M ( 3 ) l in crosses with T(Y;3)L127, but do not uncover this Minute in crosses with T(Y;3)B81 (Table

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ANALYSIS OF THE TIP OF 3 R 547

99

100

70

R?4

R?O or

671

I

I

-

67A

3

FIGURE 3.-Location of end points of the T(Y;3)B81 translocation (thin line) and the duplications (bars) used in the production of segmental deficiencies in region 99D. T h e unshaded or dotted portion for each chromosome represents the uncertainty in the location of the breakpoint. See Table 1 for the exact breakpoints of each chromosome.

Region 99E: T(Y;3)R133 and duplications R 1 4 , 6 7 A , 3, 88, 150P and 4 8 were used to construct synthetic deficiencies distal to the R 1 3 3 breakpoint. Combining the RI33 terminal deficiency with 3, 88, 150P and 48 duplications results in a moderate Minute phenotype in the heterozygotes (Table 3). T h e combination of the R 1 3 3 deficiency with R 1 4 and 6 7 A duplications gives viable heterozygotes that are non-Minute. Further mapping of the Minute was carried out using Dp(3;1)124P, which has a breakpoint at 99E4-5 between the break- points of Dp(3;1)67A and Dp(3;1)3 (Table 1). Minute Dp(3;1)3; D f ( 3 R ) R 1 3 3 / T M 6 females were crossed to Dp(3;1)124P-bearing males. T h e Minute locus is covered by the 124P duplication, because Dp(3;1)124P; Df(3R)R133/+ daugh- ters were non-Minute. T h e Minute locus, therefore, is in the 99E4-Fl region between the breakpoints of Dp(3;1)124P on the left and the breakpoint of Dp(3;1)3 on the right. Based on the proximity of the location of this Minute to that of M(3)J which has been placed at 105 on the genetic map (SCHULTZ 1929), we shall hereafter refer to this Minute at 99E as M ( 3 ) f . This represents a change in the putative location of M ( 3 ) f from the 99F-100C location pro- posed previously by LINDSLEY et al. (1972) to the 99E4-Fl interval.

T h e breakpoint of the R 1 3 3 translocation was further confirmed to be in 99E by the R133-124P and R133-67A combinations. T h e combination of the R 1 3 3 terminal deficiency with the 124P duplication is lethal when homozygous, whereas the combination R133-67A is viable when homozygous. This places the RI33 breakpoint between those of the two duplications, from 99D9 to 99E5.

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548 K . KONCSUWAN, R . P. DELLAVALLE AND J. R. MERRIAM

were used to generate overlapping deficiencies in this interval. All of these combinations result in heterozygotes that are viable and non-Minute (Table 3). However, the GI 16-3 combination remains balanced, whereas the G116-124P

combination gives viable homozygotes. Thus, the breakpoint of the T(Y;3) G116 maps between the duplications 3 and 124P, in the interval 99E4-F1.

Region 100A: T(Y;3)A113 and the 3 4 , 93, 152P, 150P, 7 9 , 1A and 4 8 du- plications were used (Table 3). T h e analysis of the deficiency-duplication com- binations in this interval indicates that there are no haplo-abnormal loci in this region (Table 3). T h e T(Y;3)A113 breakpoint in the lOOA interval cannot be established more exactly by examination of these stocks, because D f ( 3 R ) A l l 3

in combination with D P ( 3 ; l ) cannot be made homozygous. Non-balancer off- spring were not observed, even when Df(3R)A113 was combined with the longer, overlapping duplications (i.e., D P ( 3 ; 1 ) 6 7 A ) . We conclude that the

T(Y;3)A113 chromosome carries an unrelated recessive lethal mutation proxi- mal to the breakpoint.

Region IOOBC-tip of 3R: There exists at least one Minute locus in the interval between the breakpoint of T(Y;3)L129 at lOOC (Table 1) and the 3 R

tip. T h e L 1 2 9 terminal deficiency heterozygotes usually fail to survive; the rare escapers are strongly Minute. LINDSLEY et al. (1972) assigned the Minute locus

M(3)g to this interval. We cannot further investigate its location because there are no available duplications with breakpoints broken to the right of 1OOC. T h e autosomal breakpoint of L 1 2 9 was determined by combining the defi- ciency segregant of L 1 2 9 with the two duplications, 150P and 4 8 . Both com- binations give viable homozygotes. Thus, from the genetic data, the breakpoint of L 1 2 9 is to the right of (= distal to) the duplication 4 8 breakpoint that is in bands 100B7,S.

DISCUSSION

Our goal has been to obtain small synthetic deficiencies of the 99D region and the surrounding intervals from 98EF to 100B. T(Y;3)-generated terminal deficiencies were combined with a series of duplications of the right tip of chromosome 3 (e.g., Figure 3 ) . Figure 4 summarizes our data regarding the order of translocation and duplication breakpoints within the 98- 1 OOF region and the cytogenetic map of the haplo-abnormal loci in the interval. The as- sumption that combinations that are homozygous viable are overlapping du- plications allows us to further resolve their locations and the relative order of the autosomal breakpoints (Figure 4). This also provides information about the Y;3 translocation breakpoints, since cytological examination does not always give exact autosomal breakpoints, because the Y chromosome is heterochro- matic and underreplicated in salivary chromosomes.

We have divided this region of chromosome 3, comprising a total of ap- proximately 91 bands, into 18 intervals with an average of 5 bands per interval (Figure 4). Since an average band is estimated to contain 20-30 kb (BEERMANN

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ANALYSIS OF THE TIP OF 3 R 549

M f 3 ) .

m

J55‘ 8226 1L127~ 8 8 1 R133 G116 A l l 3 L 129

1 1 1 I l l I I 1 1

8152 46A 78 R14 R70 67A l24P J!. 88 $3 150P 48

6?#

3Rtip

9e

99

’90

A EF F14 8 5 6 85-9 C5-7 01-2 DI-2 D6-9 D9-EI W E 5 E4-5 E4-Fl E5F1 F6-8 F9-lD A 81-2 07-8 C I

FIGURE 4.-An expanded (not to scale) diagram summarizing the phenotypes of the segmental deficiencies. The breakpoints of rearrangements are ordered from left to right. Arrows above the horizontal axis represent the distal limits of the terminal deficiencies from Y;3 translocation chro- mosomes (extending from the left), and lines below represent proximal limits of the duplication chromosomes (extending from the right). For simplicity, a unit distance was assigned between adjacent aberrations. Adjacent breakpoints are according to genetic and/or cytological criteria, and numbers below the horizontal axis denote the cytological locations of the rearrangement breakpoints. Boxes represent extent of deficiencies and phenotypes of the heterozygotes; open box indicates inviability, dotted box indicates Minute phenotype and striped box indicates non-Minute phenotype of the deficiency-bearing heterozygotes. Each box refers to the results of one cross. Hpi = haplo-inviable region.

possible to identify clones within an interval by “walking” (BENDER, SPIERER and HOGNESS 1983) from one rearrangement breakpoint to the other.

Our results indicate that the region of the third chromosome between 98A and lOOF contains at least one haplo-inviable locus and four Minute loci. We were able to assign two Minute loci, M(3)99D and M(3)J to two intervals within 99C-F; the deficiency for both intervals is haplo-lethal (LINDSLEY et al. 1972). One of these, M(3)99D, has not been reported before. Our finding of an additional

Minute

confirms that the actual number of Minute loci in the Dro- sophila genome is somewhat greater than previously described, as suggested by LINDSLEY et al. (1972) and MOSCOSO DEL PRADO and RIPOLL (1983).

We thank JUDITH LENGYEL for her advice, encouragement and helpful suggestions concerning the manuscript, R. J. MACINTYRE, E. B. LEWIS and L. CRAYMER for advice and supplying Droso- phila stocks used in this study and ADELAIDE T. C. CARPENTER for her many constructive com- ments o n the manuscript. Support for the work and for K. KONGSUWAN is acknowledged from National Science Foundation grant PCM 2 1 8 3 0 to JUDITH LENCYEL and National Science Foun- dation grant PCM 0 3 5 3 9 to JUDITH LENCYEL and JOHN MERRIAM.

LITERATURE CITED

(12)

550

BENDER, W . , P. SPIERER and D. S. HOCNESS, 1983

K. KONGSUWAN, R . P. DELLAVALLE AND J. R. MERRIAM

Chromosome walking and jumping to isolate DNA from the Ace and rosy loci and the bithorax complex in Drosophila melanogaster. J. Mol. Biol. 168: 17-33.

Report of I.. CRAYMER. Drosophila Inform. Serv. 55: 199. CRAYMER, L., 1980

I;RISARDI, M. C. and R . J . MACINTYRE, 1948 Position effect variegation of an acid phosphatase gene in Drosophila. Mol. Gen. Genet. 197: 403-413.

JUUD, B. H., M. U'. SHEN and T . C. KAUFMAN, 1972 T h e anatomy and function of the X

chromosome of Drosophila melanogaster. Genetics 71: 139-1 56.

KANKEL, D. R. and J. C. HALL, 1976 Fate mapping of nervous system and other internal tissues in genetic mosaics of Drosophila melanogaster. Dev. Biol. 98: 1-24.

KONGSLWAN, K., QIANC Y U , A. VINCENT, M. C . FRISARDI, M. ROSBASH, J. A. LENGYEI. and J. A Drosophila Minute gene encodes a ribosomal protein. Nature 317: 555-

IXNGYEL, J., M. KOARK, K. KONGSUWAN, P. A. MAHONEY, P. D. BOYER and J. R. MERRIAM, 1985 Isolation and characterization of blastoderm-specific genes of Drosophila melanogaster: In: Bell LV. Baruche Symposium, Cellular and Molecular Biology of Invertebrate Development, Vol. 15, Edited by R. M. Sawyer and R. H. SHOWMAN. University of South Carolina Press. In press.

Insl. Wash. Publ. 627. MERRIAM, 1985 558.

LINDSLEY, 1). 1.. and E. H . GRELL, 1968 C;enetic variations of Drosophila melanogaster. Carnegie

IANDSLEY, D. L., L. SANDIER, B . S. BAKER, A . 7'. C. CARPENTER, R. E. DENELL, J. C. HALL, P. A. JACOBS, G. I.. G. MIKLOS, B. K. DAVIS, R. C. GKIHMANN, R. W. HARDY, A. HESSLER, S. W. MILLER, H. NOZAWA, D. M . PARRY and M. GOULD-SOMERO, 1972 Segmental aneuploidy and the genetic gross structure of the Drosophila genome. Genetics 71: 157-184.

Cloned DNA by chromosome location. Drosophila Inform. Serv. 61: 9- 19.

MERRIAM, J . K., 1985

Moscoso DEI. PRADO, J . and P. RIPOLL, 1983 Cytological location and lethal interactions of three Minute loci in chromosome 3 of Drosophila melanogaster. Genet. Res. 42: 59-63.

ROARK, M., P. MAHONEY, M . L. GRAHAM and J. A. LENCYEI., 1985

blastoderm-specific genes of Drosophila melanogaster. Dev. Biol. 109: 476-488.

SCHULTL, J . , 1929 14: 366-419.

SEATTLE-LA JOI.I.A DROSOPHILA LABORATORIES, 197 1

Blastoderm-differential and

The Minute reaction in the development of Drosophila melanogaster. Genetics

T h e use of Y-autosome translocations in the construction of autosomal duplications and deficiencies. Drosophila Inform. Serv. (Suppl) 47.

Molecular mapping of genetic and chromosome units in Drosophila melanogaster. J. Mol. Biol. 168: 35-50.

Sequence and structure of the serendipity locus of Drosophila melanogaster: a densely transcribed region including a blastoderm-specific gene. J. Mol. Biol. 186: 149-166.

Drosophila maternal and em- bryo niRNAs transcribed from a single transcription unit use alternate combinations of exons. EMBO J. 3: 1003-1013.

Communicating editor: A. T. C. CARPENTER SPIERER, P., A . SPIERER, U'. BENDER and D. HOCNESS, 1983

VINCENT, A., H. V. COLOT and M. ROSBASH, 1985

Figure

TABLE 1 A list of the Y;3 translocations and 3:1 duplications used to generate synthetic deficiencies and their salivary chromosome cytology
FIGURE 1 duced in Table .--Crosses used to obtain segmental deficiency stocks from Dp(3;I)s
FIGURE 2.-Genotypes males (second cross which are produced by the mating of Dp(jr;I)-bearing females with T(Y;?) of Figure 1)
TABLE 3 Progeny produced from cross tip of 3R chromosome 2 of Figure 1, in which females carrying duplications of (Dp(3;1)/x the TM3, Sb/+) are crossed with Y;3
+3

References

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