Germline and developmental roles of the nuclear transport factor importin alpha3 in C. elegans.

摘要

The importin alpha family of transport factors mediates the nuclear import of classical nuclear localization signal-containing proteins. In order to understand how multiple importin alpha proteins are regulated both in individual cells and in a whole organism, the three importin alpha (ima) genes of Caenorhabditis elegans have been identified and studied. All three IMAs are expressed in the germline; however, only IMA-3 is expressed in the soma. RNA interference (RNAi) experiments demonstrate that IMA-3 is required for the progression of meiotic prophase I during oocyte development. Loss of IMA-3 expression leads also to a disruption of the nuclear pore complex accompanied by the mis-localization of P granules. A range of defects occurring in ima-3(RNAi) F1 progeny further supports a role for IMA-3 during embryonic and larval development. The functional association of IMA-3 with distinct cellular events, its expression pattern and intracellular localization indicate that regulation of the nuclear transport machinery is involved in the control of developmental pathways.