期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2010
卷号：107
期号：28
页码：12570-12575
DOI：10.1073/pnas.1007935107
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Although mammalian polypyrimidine tract-binding (PTB) protein functions in most or all cell types to regulate a wide spectrum of transcripts, Drosophila PTB encodes an abundant male germline-specific mRNA isoform (dmPTB) whose expression correlates with male fertility. The biological function of this isoform is unknown. Using selection-amplification, we show that mammalian and Drosophila PTB have similar RNA sequence preference, suggesting that cell-specific expression rather than unique RNA-binding properties account for the sex-specific function of dmPTB. We also show that the dmPTB protein isoform expressed in the male germline is by far the most abundant isoform, and reduction of its levels correlates with male sterility. Finally, we show that dmPTB expression is necessary for proper spermatid individualization, the terminal step necessary for production of motile sperm. Loss of dmPTB results in severe disruption of the actin cones of the spermatid individualization complex. This represents a cytological defect resulting from PTB loss. We discuss the basis for functional differences between mammalian and Drosophila PTB orthologs.
关键词：individualization complex ; spermatogenesis ; male germline ; selection–amplification ; RNA binding protein
