SPK-1, a C-elegans SR protein kinase homologue, is essential for embryogenesis and required for germline development

SR-protein kinases (SRPKs) and their substrates, serine/arginine-rich pre-m RNA splicing factors, are key components of splicing machinery and are well conserved across phyla. Despite extensive biochemical investigation, the p hysiological functions of SRPKs remain unclear. In the present study, cDNAs for SPK-1, a C. elegans SRPK homologue, and CeSF2, an SPK-1 substrate, wer e cloned. SPK-1 binds directly to and phosphorylates the RS domain of CeSF2 in vitro. Both spk-1 and CeSF2 are predominantly expressed in germlines. R NA interference (RNAi) experiments revealed that spk-1 and CeSF2 play an es sential role at the embryonic stage of C. elegans. Furthermore, RNAi studie s demonstrated that spk-1 is required for germline development in C. elegan s. We provide evidence that RNAi, achieved by the soaking of L1 larvae, is beneficial in the study of gene function in post-embryonic germline develop ment. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.