Roles of retinoic acid receptors and of Hox genes in the patterning of the teeth and of the jaw skeleton







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Fig. 3. Effect of a syntheticretinoid(Ch55) at a finalconcentrationof 10.9M on toothmorphogenesisin a chemically-definedculturemedium.Frontalhistological sectionsthrough13.0dpc first lower molars insitu(a), and after 10 days inculture (b and c) Bither in t

Fig 3.

Effect of a syntheticretinoid Ch55 at a finalconcentrationof 10 9M on toothmorphogenesisin a chemically definedculturemedium Frontalhistological sectionsthrough13 0dpc first lower molars insitu a and after 10 days inculture b and c Bither in t. View in document p.4
Fig. 3a-c.). Italso permits the normal asymmetricaldevelopmentthe lingual and labial sides in incisor explants (Bloch-Zupan1994b)
Fig 3a c Italso permits the normal asymmetricaldevelopmentthe lingual and labial sides in incisor explants Bloch Zupan1994b . View in document p.5
Fig. 5. Schematicrepresentationthe 2nd pharyngealparedrespectively;orthotopic and ectopic tympanic bone; X

Fig 5.

Schematicrepresentationthe 2nd pharyngealparedrespectively orthotopic and ectopic tympanic bone X. View in document p.6
Fig. 6, Medial(a,b)computerstapedialpossessesandcaudalIc)aspectsofthree-dimensionalreconstructionsfrom serial histologicalsectionsof the leftincudo-mallearcomplexin 18,5dpc wildtype(a) andHoxa-2nullmutantmice(b andcl.The mutantincudesarefusedonlyat thetipof theirprocesses(SI and 512) andthuseachmoietyof the doubleincusits ownbody(BI and B12) and caudalprocess(CI andCI2).In (c),wehaverepresentedthecaudal-mostportionofthepterygoquadrate(upperjaw)element(PO)to showits proximityto the caudalincus.The twomutantmalleiare fusedatthe levelof theirmanubrium(MM)andthuseachmoietyof the doublemalleuspossessesits ownhead(HMand HM2) andneck(NMandNM2)butlackstheprocessusbrevis(PB).Themutantdoublemalleusis continuousrostrallywiththeorthotopicMeckel'scarti-lage(MC,notethatonlythe caudal-mostportionof the Meckel'scartilagehas been reconstructed)andcaudallywithan ectopictruncatedMeckel'scartilage(MC2),reconstructedcompletely.The arrowpointsrostrally(i.e.towardsthe snout);the openarrowpointsventrally(i.e.towardsthe neck).

Fig 6.

Medial a b computerstapedialpossessesandcaudalIc aspectsofthree dimensionalreconstructionsfrom serial histologicalsectionsof the leftincudo mallearcomplexin 18 5dpc wildtype a andHoxa 2nullmutantmice b andcl The mutantincudesarefusedonlyat thetipof theirprocesses SI and 512 andthuseachmoietyof the doubleincusits ownbody BI and B12 and caudalprocess CI andCI2 In c wehaverepresentedthecaudal mostportionofthepterygoquadrate upperjaw element PO to showits proximityto the caudalincus The twomutantmalleiare fusedatthe levelof theirmanubrium MM andthuseachmoietyof the doublemalleuspossessesits ownhead HMand HM2 andneck NMandNM2 butlackstheprocessusbrevis PB Themutantdoublemalleusis continuousrostrallywiththeorthotopicMeckel scarti lage MC notethatonlythe caudal mostportionof the Meckel scartilagehas been reconstructed andcaudallywithan ectopictruncatedMeckel scartilage MC2 reconstructedcompletely The arrowpointsrostrally i e towardsthe snout the openarrowpointsventrally i e towardsthe neck . View in document p.7
Fig. 7. Frontalsectionsthroughtheheadof 14.5dpcfetusesatthelevelof theexternalauditorymeatus.(a)Wildtypefetus.(b) Hoxa-2nul,'fetus.fA and EA2, orthotopicand supernumeraryexternalauditorymeatusrespectively.MM, manubriumof themalleus.

Fig 7.

Frontalsectionsthroughtheheadof 14 5dpcfetusesatthelevelof theexternalauditorymeatus a Wildtypefetus b Hoxa 2nul fetus fA and EA2 orthotopicand supernumeraryexternalauditorymeatusrespectively MM manubriumof themalleus . View in document p.8
Fig. 8. Lateral(a and b) and caudalt) aspectstologicalprocessusand of the mutantpresencestapediusprocessusstapes;stapediusrostrally (i.e

Fig 8.

Lateral a and b and caudalt aspectstologicalprocessusand of the mutantpresencestapediusprocessusstapes stapediusrostrally i e. View in document p.9
Fig.theby 2nd arch
Fig theby 2nd arch. View in document p.10