THE DROSOPHILA TRITHORAX GENE ENCODES A CHROMOSOMAL PROTEIN AND DIRECTLY REGULATES THE REGION-SPECIFIC HOMEOTIC GENE FORK HEAD
THE DROSOPHILA TRITHORAX GENE ENCODES A CHROMOSOMAL PROTEIN AND DIRECTLY REGULATES THE REGION-SPECIFIC HOMEOTIC GENE FORK HEAD
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DOI：
10.1101/gad.8.20.2478
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发表时间：
1994-10-15
影响因子：
10.5
通讯作者：
MAZO, A
中科院分区：
文献类型：
--
作者：
KUZIN, B;TILLIB, S;MAZO, A
果蝇基因trithorax的活性需要保持适当的空间模式的表达的多个同源异型基因的双胸和双足复合体。三胸编码两种>400 kD的大蛋白同种型。我们在幼虫唾液腺多线染色体上的16个离散位点检测到了其产物，其中12个位点与几种Polycomb组蛋白的结合位点共定位。在携带另一个三胸组基因ash-1和Polycomb组基因pco/E（z）突变的幼虫中，三胸蛋白结合的强度强烈降低。一个强大的三胸结合位点被发现在叉头基因，区域特异性同源异型基因不位于同源异型复合体的细胞学位置。进一步的分析表明，三胸蛋白结合在异位位点携带叉头序列在转化系。三胸结合发生在一个8.4 kb的调控区域内，该区域指导包括唾液腺在内的几种胚胎组织中的叉头表达。因此，内源性叉头RNA的表达在三胸突变体胚胎和幼虫组织中大大降低。这些结果表明，三胸通过与其调控区的相互作用维持靶基因的表达，并且这种相互作用取决于至少一些其他三胸和多梳组蛋白的存在。
The activity of the Drosophila gene trithorax is required to maintain the proper spatial pattern of expression of multiple homeotic genes of the Bithorax and Antennapedia complexes. trithorax encodes two large protein isoforms of >400 kD. We have detected its products at 16 discrete sites on larval salivary gland polytene chromosomes, 12 of which colocalize with binding sites of several Polycomb group proteins. The intensity of trithorax protein binding is strongly decreased in larvae carrying mutations in another trithorax group gene ash-1, and in the Polycomb group gene pco/E(z). A strong trithorax binding site was found at the cytological location of the fork head gene, a region-specific homeotic gene not located within a homeotic complex. Further analysis showed that trithorax protein binds at ectopic sites carrying fork head sequences in transformed lines. Trithorax binding occurs within an 8.4-kb regulatory region that directs fork heed expression in several embryonic tissues including salivary glands. Consistently, expression of endogenous fork head RNA is greatly reduced in trithorax mutant embryos and in larval tissues. These results show that trithorax maintains expression of target genes by interaction with their regulatory regions and that this interaction depends on the presence of at least some of the other trithorax and Polycomb group proteins.