The selection, expression, and organization of a set of head-specific genes in Drosophila☆

[摘要] ComparativescreeningofalibraryofclonedDrosophilaDNAwithpolyadenylatedmRNAfromDrosophilaadultheadandadultbodyidentified20clonedsequencesexpressedmoreabundantlyinthetissuesoftheheadthaninothertissues.Quantitationusinga“dotblot”hybridizationassaydemonstratedthattheDNAsequencesareexpressedonadultheadpolysomesfrom3to177timesmoreabundantlythanonbodypolysomes,andtheirtranscriptsrepresentfrom0.05to0.66%ofthepolyadenylatedmRNAmassofthehead.Thesteady-statenuclearRNAconcentrationsoffourspeciesweredeterminedtobefrom13to48timesgreaterinheadnucleithaninbodynuclei,anindicationthattheirexpressioniscontrolledatleastinpartatthetranscriptionallevel.Thechromosomallocationsofall20head-specificcloneswereidentifiedbyinsitumapping,andnodistinctclusteringwasobserved.However,fourofthecloneswereshownbySouthernandNorthernblotanalysistocontainmultipleRNAcodingsequences.Thegenesinthesetightlyclusteredsetswereobservedtobeexpressedsimultaneouslyinsomecasesanddifferentlyinothers.

[学科分类] 生物科学（综合）