Four distinct regions in the auxiliary domain of heterogeneous nuclear ribonucleoprotein C-related proteins.

A 306 amino acid sequence deduced from a rabbit bladder cDNA is 98% identical to the human heterogeneous nuclear ribonucleoprotein (hnRNP) C2. The sequence comparison of the hnRNP C-related proteins reveals four distinct regions in the C-terminal auxiliary domain. The region next to the N-terminal RNA-binding domain is variable in length. Following the variable region, a basic region and a leucine zipper are conserved in all hnRNP C-related proteins including mouse and human Raly. Several Lys-Ser-Gly repeats are present in the basic region of the hnRNP C proteins. The C-terminal region is more divergent between hnRNP C and Raly. Signature sequences and possible functions are proposed for the different regions of the hnRNP C proteins.