Zhang Y, Ferreira H B, Greenstein D, Chisholm A, Emmons S W
Department of Molecular Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
Mech Dev. 1998 Nov;78(1-2):179-87. doi: 10.1016/s0925-4773(98)00171-3.
It is shown that the C. elegans Pax-6 locus encodes two protein isoforms. One contains a Paired DNA binding domain as well as a homeodomain; the other consists only of the carboxy-terminal portion of the locus encoding the homeodomain. These two isoforms are expressed in a variety of postembryonic cell lineages. In one set of lineages, nuclear localization of a homeodomain-only form (MAB-18 isoform) appears to be under temporal and spatial control. Nuclear localization of MAB-18 is correlated with the genetic requirement for mab-18 and with activation of a reporter gene driven by a mab-18 promoter. Reporter gene expression is dependent on mab-18 gene activity. It is hypothesized that a positive feedback loop is activated by regulated nuclear entry.
研究表明，秀丽隐杆线虫的Pax-6基因座编码两种蛋白质异构体。一种包含一个配对DNA结合结构域以及一个同源结构域；另一种仅由编码同源结构域的基因座的羧基末端部分组成。这两种异构体在多种胚胎后细胞谱系中表达。在一组谱系中，仅含同源结构域形式（MAB-18异构体）的核定位似乎受到时间和空间的控制。MAB-18的核定位与mab-18的遗传需求以及由mab-18启动子驱动的报告基因的激活相关。报告基因的表达依赖于mab-18基因的活性。据推测，一个正反馈环是由受调控的核进入激活的。
