Arya Gunjan H, Lodico Matthew J P, Ahmad Omar I, Amin Rohul, Tomkiel John E
Biology Department, University of North Carolina, Greensboro, North Carolina 27420, USA.
Genetics. 2006 Sep;174(1):125-34. doi: 10.1534/genetics.106.061556. Epub 2006 Jul 2.
Drosophila melanogaster males lack recombination and have evolved a mechanism of meiotic chromosome segregation that is independent of both the chiasmatic and achiasmatic segregation systems of females. The teflon (tef) gene is specifically required in males for proper segregation of autosomes and provides a genetic tool for understanding recombination-independent mechanisms of pairing and segregation as well as differences in sex chromosome vs. autosome segregation. Here we report on the cloning of the tef gene and the molecular characterization of tef mutations. Rescue experiments using a GAL4-driven pUAS transgene demonstrate that tef corresponds to predicted Berkeley Drosophila Genome Project (BDGP) gene CG8961 and that tef expression is required in the male germ line prior to spermatocyte stage S4. Consistent with this early prophase requirement, expression of tef was found to be independent of regulators of meiotic M phase initiation or progression. The predicted Tef protein contains three C2H2 zinc-finger motifs, one at the amino terminus and two in tandem at the carboxyl terminus. In addition to the zinc-finger motifs, a 44- to 45-bp repeat is conserved in three related Drosophila species. On the basis of these findings, we propose a role for Tef as a bridging molecule that holds autosome bivalents together via heterochromatic connections.
黑腹果蝇雄性缺乏重组,并进化出一种减数分裂染色体分离机制,该机制独立于雌性的交叉和非交叉分离系统。teflon(tef)基因在雄性中是常染色体正确分离所特需的,为理解配对和分离的非重组机制以及性染色体与常染色体分离的差异提供了一种遗传工具。在此,我们报告tef基因的克隆及tef突变的分子特征。使用GAL4驱动的pUAS转基因进行的拯救实验表明,tef对应于预测的伯克利果蝇基因组计划(BDGP)基因CG8961,且在精子发生细胞阶段S4之前的雄性生殖系中需要tef表达。与这一早期前期需求一致,发现tef的表达独立于减数分裂M期起始或进展的调节因子。预测的Tef蛋白包含三个C2H2锌指基序,一个在氨基末端,两个在羧基末端串联。除了锌指基序外,一个44至45bp的重复序列在三个相关果蝇物种中保守。基于这些发现,我们提出Tef作为一种桥接分子的作用,通过异染色质连接将常染色体二价体聚集在一起。