GENES ANCESTRAL TO THE THYROID/STEROID RECEPTOR FAMILY

我们小组一直在调查甲状腺/类固醇激素的成员 受体家族在低等生物中，试图分析结构 和最原始的受体的功能，更好地了解 脊椎动物中存在的无数受体的功能。我们克隆 秀丽隐杆线虫中三种这样的蛋白质的cDNA。一 其中CHR 3与果蝇的DHR 3和MHR 3高度同源 在六度曼杜卡果蝇中的这种受体是由蜕皮激素诱导的。 我们克隆的另一个受体（CNR 14）与E78 A受体同源， 果蝇中可诱导的蜕皮激素。 第三种受体CNR 8与此类似， 脊椎动物的早期反应基因NAK 1。受体处于 北方分析表明，最近，我们克隆了 CHR 3和CNR 14的基因，我们正在研究它们的启动子。 我们发现 CHR 3和CNR 14这两个基因是反式剪接的， 操纵子 而CHR 3与前导序列SL 2反式剪接，并且 CNR 14与SL 1反式剪接，CNR 8似乎转录为单个的 成绩单。 顺反子转录让我们有机会研究 由共同启动子转录的基因， 一起工作。我们将CHR 3定位于1号染色体的中心区域， 与hlh-2基因关系密切，一种类似于E12同源盒蛋白 蛋白质，脊椎动物中MyoD的伴侣。 我们证实了 hlh-2和CHR 3的接近度通过粘粒上的PCR测定。有趣的是，一些 已知在该区域缺失的突变体是致命的。我们目前正在 使用卵巢微注射研究CHR 3和CNR 14的表达 可能的启动子区与DNA序列偶联的雌雄同体 编码β-半乳糖苷酶我们也希望使用杂合菌株 在CHR 3定位的区域中具有缺失，用于敲除研究， 救援 我们继续研究立方水母的类固醇激素受体 赤藓 我们克隆了至少两种cDNA异构体， 基因 据我们所知，这是他体内唯一一个这样的基因， 生物体，可以代表最原始的成员， 甲状腺/视黄酸亚家族。

Our group has been investigating members of thyroid/steroid hormone receptor family in lower organisms in an attempt to analyze the structure and functions of the most primitive receptors, better to understand the function of the myriad of receptors present in the vertebrata. We cloned cDNAs for three such proteins in the nematode Caenorhabditis elegans. One of them (CHR3) is highly homologous to the DHR3 in Drosophila and MHR3 in Manduca sexta. This receptor in Drosophila is induced by ecdysone. Another receptor we cloned (CNR14) is homologous to E78A receptor, also ecdysone inducible in Drosophila. The third receptor, CNR8 is similar to an early response gene in vertebrates, NAK1. The receptors are stage specific as shown by Northern analysis. More recently, we have cloned the genes for CHR3 and CNR14 and we are studying their promoters. We found that two genes, CHR3 and CNR14 are trans-spliced and so are organized in operons. While CHR3 is trans-spliced with a leader sequence SL2, and CNR14 is trans-spliced with SL1, CNR8 seems to be transcribed as single transcript. Cistronic transcription gives us the opportunity to study the genes which are transcribed from a common promoter and which could function together. We mapped CHR3 to the center region of chromosome 1 in close relation to hlh-2 gene, a homeobox protein analogous to E12 protein, the partner of MyoD in vertebrates. We confirmed the propinquity of the hlh-2 and CHR3 by PCR on a cosmid. Interestingly, some known mutants with deletion in this region are lethal. We are currently studying expression of CHR3 and CNR14 using microinjetions to the ovary of hermaphrodites with probable promoter regions coupled to DNA sequence coding for beta-galactosidase. We also hope to use heterozygotic strains with deletions in a region where CHR3 maps for a study of knock-out and rescue. We continued on the steroid hormone receptor in cubomedusan jellyfish Tripedalia cystophora. We cloned at least two cDNA isoforms and most of the gene. As far as we can tell, this is the only such gene in his organism and could represent the most primitive member of thyroid/retinoic acid subfamily.