lin 4 independent translational repression of lin 28

描述（由申请人提供） In C.异时性调节线虫胚胎后发育时间 基因. lin-28的时间下调对于执行 幼虫阶段3（L3）程序，一种独立于lin-4新途径， 核激素受体DAF-12抑制LIN-28。其目的是 建议是确定lin-4独立的分子机制 抑制（LIR）的lin-28，并确定基因的必要性，这一时间 机制首先，假设将被测试，daf-12预防性地 抑制lin-28，从而指定进入L3阶段。为了验证这个，我 将分析lin-28 mRNA和蛋白质水平在幼虫发育过程中， 野生型和DAF-12突变基因型。第二，对假设进行检验 lin-28的3' UTR中的元件对于LIR依赖性的表达是足够的。 下调lin-28，并且是进入L3所必需的。GFP报告 具有完整或截短的lin-28 3 ′ UTR序列的构建体将用于 测试充分性并确定具体的LIR要素。最后，基因筛查 将进行识别LIR途径的新组件。这项建议 具有令人兴奋的潜力，以确定新的小的时间RNA调节剂， 发展时机，这是一种常见的监管模式， 老鼠对人

DESCRIPTION (provided by applicant) In C. elegans post-embryonic developmental timing is regulated by heterochronic genes. The temporal downregulation of lin-28 is necessary for the execution of the larval stage 3 (L3) program, a novel pathway independent of lin-4 involving the nuclear hormone receptor daf-12 acts to repress lin-28. The aims of this proposal are to determine the molecular mechanism of lin-4-independent repression (LIR) of lin-28 and to identify genes essential for this timing mechanism. First, the hypothesis will be tested that daf-12 translationally represses lin-28 and thereby specifies entry into the L3 stage. To test this, I will analyze lin-28 mRNA and protein levels during larval development in wildtype and daf-12 mutant genotypes. Secondly, the hypothesis will be tested that elements in the 3' UTR of lin-28 are sufficient for LIR-dependent downregulation of lin-28 and are required for entry into L3. GFP reporter constructs with intact or truncated lin-28 3' UTR sequences will be used to test sufficiency and identify specific LIR elements. Lastly, a genetic screen will be performed to identify new components of the LIR pathway. This proposal has the exciting potential to identify new small temporal RNAs regulators of developmental timing, which is emerging as a common mode of regulation from mouse to man.