GENES ANCESTRAL TO THE THYROID/STEROID RECEPTOR FAMILY

我们继续研究核激素的性质和功能 原始形式的受体。在线虫类线虫中，我们有 分离并测序了chr3基因(现在称为nhr23)。转基因 对受体基因的研究表明，正确的表达需要大约 600个碱基对位于第一个起始位点的上游 第一个内含子。启动外显子I上游的转录产物是 转录到推测的蛋氨酸上游的SL1 35碱基对 发起人。上游还有第二个SL1剪接位点BP 预测蛋氨酸在第二外显子。来自这两个人的信息 在混合阶段的RNA中，剪接反应似乎大致相同。 抗体研究表明，chr3蛋白总是定位于 细胞核，在早期发育中母性表达，几乎 仅在胚胎和成人的皮下细胞中表达。过剩 热休克启动子表达chr3蛋白导致松弛 角质层和水泡表型。对Chr3表达的抑制作用 转基因RNA会导致角质层残留和体型失调 监管。我们推断chr3蛋白参与了裂解。 角质层脱落所需。这可能会成为 一种控制自由生活线虫的方法 马铃薯、甜菜和棉花的害虫。我们还继续进行了 标题蛇床子属植物的研究。从雷公藤中分离到的MSTR-1基因已经测序 并被证明类似于RXR核受体家族；此外 我们已经证明它结合了9顺式维甲酸和纳米分子。 亲和力。初步数据表明，它在 虽然这些形式的生物测定，但扁平线虫的变态为息肉 很难控制。我们还演示了Mstr 1结合 到核苷酸序列。

We have continued our work on the nature and function of nuclear hormone receptors in primitive forms. In the nematode C elegans we have isolated and sequenced the gene chr3 (now known as nhr 23). Transgenic studies with receptor genes show that proper expression requires about 600 base pairs upstream of the first initiation start site and all of the first intron. The transcript initiating upstream of exon I is transpliced to SL1 35 base pairs upstream of the putative methionine initiator. There is a second SL1 splice site bp upstream of the predicted methionine in the second exon. The message from these two splicing reactions appear to be about equal in mixed stage RNA. Antibody studies show that chr3 protein is always localized to the nucleus, is maternally expressed in early development and is almost exclusively expressed in hypodermal cells in embryo and adult. Excess expression of chr3 protein by a heat shock promoter causes loosened cuticle and a blister phenotype. Inhibition of chr3 expression with transgenic RNA produces retained cuticle and disorders of body size regulation. We conclude that chr3 protein is involved in the lysis required for cuticle shedding. It is possible that this may serve as an approach to controlling free living nematodes which are an important pest of potatoes, beets and cotton. We have also continued with studies of cnidaria. Mstr 1 isolated from tripedilia has been sequenced and shown to resemble the RXR family of nuclear receptors; furthermore we have demonstrated that it binds 9cis retinoic acid with nanomolar affinity. Preliminary data suggest that it plays a role in the metamorphosis of planulae into polyps although bioassay of these forms is difficult to control. We also have demonstrated that mstr 1 binds to nucleotide sequences.