DEFECTS IN EMBRYOGENESIS IN MUTANTS ASSOCIATED WITH THE ANTENNAPEDIA GENE-COMPLEX OF DROSOPHILA-MELANOGASTER
DEFECTS IN EMBRYOGENESIS IN MUTANTS ASSOCIATED WITH THE ANTENNAPEDIA GENE-COMPLEX OF DROSOPHILA-MELANOGASTER
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DOI：
10.1016/0012-1606(84)90182-9
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发表时间：
1984-01-01
影响因子：
2.7
通讯作者：
KAUFMAN, TC
中科院分区：
文献类型：
--
作者：
WAKIMOTO, BT;TURNER, FR;KAUFMAN, TC
用扫描电镜（SEM）观察了黑腹龙骨多烯段84A-84B1,2基因突变或缺失个体的胚胎发生情况。染色体3的这一区域的发育功能是特别有趣的，因为它包含触角基因复合体（ANT-C），一个基因簇，包括同源的喙（pb），性梳减少（Scr）和触角（Antp）位点。扫描电镜（SEM）、克隆分析和温度转移实验结果表明，位于pb和Scr之间的fushi tarazu （ftz）和zerknullt （zen）基因参与了胚胎发生过程。ftz+的活性似乎需要在发育的前4小时内在胚胎胚芽带建立适当数量的片段。有ftz突变或缺陷的个体只产生正常数量的一半。每个片段是正常宽度的两倍，显然是由通常形成2个独立的元粒的细胞组成的。zen等位基因大约需要2-4小时的胚胎发生。该基因的突变导致原肠胚形成过程中形态发生运动的紊乱。突变型的特征是没有视叶，头段内化缺陷，在某些情况下，胚芽带伸长失败。在胚胎发生过程中，存在于84A-84B1,2多肽区间的其他基因的活性是必需的，这是由染色体缺陷个体的杂合或纯合表型所提示的。利用Df(3R)AntpNs+R17, Df(3R)Scr和Df(3R)ScxW+RX2的缺陷，研究了删除84A-84B1,2区间的远端部分或全部的影响。缺失杂合子的缺陷表明，要完成正常的头部退化，需要84B1,2双联体内或邻近的某些基因的野生型活性，而不是zen。缺失84A5-84B1,2区间的所有基因座会导致胚胎颌头附属物的形态和形态发生严重异常。与ANT-C相关的基因突变和缺陷对胚胎发生有着深远的影响。突变表型表明，84A-84B1,2基因的野生型等位基因除了确保适当的片段识别外，对胚芽带的正常分节和伸长以及正常的头部退化是必需的。
Embryogenesis in individuals with mutations or deficiencies of the genes in the polytene interval 84A-84B1,2 of D. melanogaster was examined using scanning electron microscopy (SEM). The developmental function of this region of chromosome 3 is of particular interest since it contains the antennapedia gene complex (ANT-C), a gene cluster that includes the homoeotic proboscipedia (pb), Sex combs reduced (Scr) and Antennapedia (Antp) loci. Results of SEM studies, clonal analyses and temperature-shift experiments show that the fushi tarazu (ftz) and zerknullt (zen) genes, which map between pb and Scr, are involved in processes initiated during embryogenesis. Activity of ftz+ appears to be required within the first 4 h of development for the establishment of the proper number of segments in the embryonic germ band. Individuals with ftz mutations or deficiencies produce only half the normal number of segments. Each of the segments is twice the normal width and is apparently comprised of cells that would normally form 2 separate metameres. The zen allele is required for about 2-4 h of embryogenesis. Mutations of this gene result in disturbances of morphogenetic movements during gastrulation. The mutant phenotype is characterized by the absence of the optic lobe, defects in involution of the head segments, and in some cases, failure of germ band elongation. A requirement during embryogenesis for the activities of other genes residing in the 84A-84B1,2 polytene interval is suggested by the phenotypes of individuals heterozygous or homozygous for chromosomal deficiencies. Using the deficiencies Df(3R)AntpNs+R17, Df(3R)Scr and Df(3R)ScxW+RX2, effects were examined of deleting the distal portions or all of the 84A-84B1,2 interval. Defects in deletion heterozygotes suggest that the wild-type activity of some gene(s) other than zen, within or just adjacent to the 84B1,2 doublet, is required to complete normal head involution. Deletion of all the loci in the 84A5-84B1,2 interval results in grossly abnormal morphology and morphogenesis of the gnathocephalic appendages of the embryo. Mutations and deficiencies of genes associated with the ANT-C have profound effects on embryogenesis. The mutant phenotypes suggest, in addition to ensuring proper segment identity, the wild-type alleles of the 84A-84B1,2 genes are necessary for normal segmentation and elongation of the germ band and normal head involution.