IDENTIFICATION OF TESTIS-SPECIFIC (LIMK2T) AND BRAIN-SPECIFIC (LIMK2C) ISOFORMS OF MOUSE LIM-KINASE-2 GENE TRANSCRIPTS

LIM-kinase 1 (LIMK1) and LIM-kinase 2 (LIMK2) are members of a novel s erine/threonine kinase subfamily with structural features composed of N-terminal two LIM domains, an internal PDZ-like domain, and a C-termi nal protein kinase domain. We recently identified and characterized th e mouse Limk2 gene and two Limk2 transcripts (Limk2a and Limk2b) codin g for proteins with distinct N-terminal LIM structures. Here we descri be two additional transcripts of the mouse Limk2 gene. One is a 1.7-kb transcript, termed Limk2t, which is specifically expressed in the tes tis and codes for an N-terminally truncated form of LIMK2 consisting o f only a part of a PDZ-like domain and a protein kinase domain. The ot her is a transcript, termed Limk2c, which is specifically expressed in the brain and codes for a protein with a 6-amino-acid insert within t he protein kinase domain. Exons specific to the 5'-terminal extra sequ ence of Limk2t and the insert sequence of Limk2c locate between exons 5-6 and exons 8-9 in the mouse Limk2 gene, respectively. Testis- and b rain-specific expression of Limk2t and Limk2c suggests specific roles in these tissues. (C) 1998 Academic Press.