Lakhotia S C, Chowdhuri D K, Burma P K
Department of Zoology, Banaras Hindu University, Varanasi, India.
Chromosoma. 1990 Aug;99(4):296-305. doi: 10.1007/BF01731706.
Effect of mutations at the ebony or black locus on induction of heat shock puffs in polytene nuclei of salivary glands of Drosophila melanogaster larvae were examined by [3H]uridine autoradiography. The levels of beta-alanine in the body are known to be increased by mutation at the ebony locus but decreased by mutation at the black locus. The presence of mutant allele/s at either locus in the homo- or heterozygous condition prevented induction of the 93D puff by heat shock. Elimination of the mutant allele at the ebony or black locus by recombination or by reversion of a P element insertion mutant allele of ebony restored the heat shock inducibility of the 93D puff. In vivo or in vitro administration of excess beta-alanine to salivary glands of wild-type larvae also resulted in the 93D site being refractory to heat shock induction. In agreement with earlier results, non-induction of the 93D puff during heat shock due to the beta-alanine effect was accompanied by unequal puffing of the 87A and 87C loci. The selective inducibility of the 93D puff by benzamide was not affected by ebony or black mutations or by excess beta-alanine in wild-type larvae.
通过[3H]尿苷放射自显影术，研究了黑檀体或黑身基因座突变对黑腹果蝇幼虫唾液腺多线核中热休克胀泡诱导的影响。已知黑檀体基因座突变会使体内β-丙氨酸水平升高，而黑身基因座突变则会使其降低。在纯合或杂合状态下，任一基因座存在突变等位基因都会阻止热休克诱导93D胀泡。通过重组或黑檀体P元件插入突变等位基因的回复突变消除黑檀体或黑身基因座的突变等位基因，可恢复93D胀泡的热休克诱导能力。对野生型幼虫的唾液腺进行体内或体外过量β-丙氨酸给药，也会导致93D位点对热休克诱导产生抗性。与早期结果一致，由于β-丙氨酸效应，热休克期间93D胀泡不被诱导，同时87A和87C基因座胀泡不均等。苯甲酰胺对93D胀泡的选择性诱导不受黑檀体或黑身突变或野生型幼虫中过量β-丙氨酸的影响。
