Zachar Z, Chou T B, Kramer J, Mims I P, Bingham P M
Department of Biochemistry and Cell Biology, University of New York, Stony Brook 11794-5215.
Genetics. 1994 May;137(1):139-50. doi: 10.1093/genetics/137.1.139.
The Drosophila suppressor-of-white-apricot [su(wa)] protein regulates/modulates at least two somatic RNA processing events. It is a potent regulator of its own expression. We report here new studies of this autoregulatory circuit. Among other things, our studies show the following. First, new evidence that su(wa) expression is autoregulated at the level of pre-mRNA splicing is reported. su(wa) protein represses accumulation of the fully spliced su(wa) mRNA encoding it and promotes accumulation of high levels of incompletely spliced su(wa) pre-mRNA. Second, the fully spliced su(wa) mRNA is sufficient for all known su(wa) genetic functions indicating that it encodes the sole su(wa) protein. Third, the incompletely spliced su(wa) pre-mRNAs resulting from autoregulation are not translated (probably as a result of nuclear retention) and apparently represent nonfunctional by-products. Fourth, the special circumstances of su(wa) expression during oogenesis allows maternal deposition exclusively of fully spliced su(wa) mRNA. Fifth, su(wa) protein immunolocalizes to nuclei consistent with its being a direct regulator of pre-mRNA processing. We discuss the implications of our results for mechanisms of splicing regulation and for developmental control of su(wa) expression.
果蝇白杏色抑制因子[su(wa)]蛋白至少调节两种体细胞RNA加工事件。它是自身表达的有效调节因子。我们在此报告对这一自动调节回路的新研究。我们的研究尤其显示了以下内容。首先，报告了新的证据，表明su(wa)的表达在mRNA前体剪接水平上受到自动调节。su(wa)蛋白抑制编码它的完全剪接的su(wa) mRNA的积累，并促进高水平不完全剪接的su(wa) mRNA前体的积累。其次，完全剪接的su(wa) mRNA足以实现所有已知的su(wa)遗传功能，这表明它编码唯一的su(wa)蛋白。第三，自动调节产生的不完全剪接的su(wa) mRNA前体不会被翻译（可能是由于核滞留），显然代表无功能的副产物。第四，卵子发生过程中su(wa)表达的特殊情况使得完全剪接的su(wa) mRNA仅通过母体沉积。第五，su(wa)蛋白免疫定位在细胞核中，这与其作为mRNA前体加工的直接调节因子一致。我们讨论了我们的结果对剪接调节机制和su(wa)表达的发育控制的影响。
