This entry represents the RNA recognition motif (RRM) of the C. elegans RNA binding protein Fox (feminizing locus on X)-1 and its homologues. The Fox-1 family proteins are evolutionarilyconserved regulators of tissue-specific alternative splicing in metazoans []. They bind specifically to an RNA element, UGCAUG []. In mammals, there are three Fox-1 homologues, RBFOX1-3 (RNA binding protein Fox-1 homologue 1-3). RBFOX1 is predominantly expressed in neurons, skeletal muscle and heart []. RBFOX1 binds to the C terminus of ataxin-2 and forms an ataxin-2/A2BP1 complex involved in RNA processing []. RBFOX2 is expressed in ovary, whole embryo, and human embryonic cell lines in addition to neurons and muscle []. RBFOX2 activates splicing of neuron-specific exons []. RBFOX3 is a nuclear RNA-binding protein that regulates alternative splicing of the RBFOX2 pre-mRNA, producing a message encoding a dominant negative form of the RBFOX2 protein. Its message is detected exclusively in post-mitotic regions of embryonic brain []. RBFOX3 modulates brain and muscle-specific splicing of exon EIIIB of fibronectin, exon N1 of c-src, and calcitonin/CGRP []. Members in this family harbour one RNA recognition motif (RRM).
