Structure of a mammalian c-rel protein deduced from the nucleotide sequence of murine cDNA clones

The avian retrovirus, rev-T, which carries the viral oncogene v-rel, causes an acute leukemia in birds and transforms immature lymphoid cells in vitro. Although the role of c-rel in normal cells is unknown, homology with the Drosophila gene dorsal, which is involved in determining embryonic dorsal-ventral polarity, raises the possibility that c-rel in vertebrates may play a role in differentiation. As a step towards understanding its role in mammalian cells, we have characterized the coding domain of the 7.5 kb murine c-rel mRNA by isolating cDNA clones that span its entire coding domain and part of the 5' and 3' untranslated regions. The nucleotide sequence reported here indicates that murine c-rel encodes a 588 amino acid polypeptide with a predicted molecular weight of 66 kd. The murine protein shares homology with avian v-rel and dorsal over a 300 amino acid stretch within the amino terminus, while the carboxyl terminal regions of these proteins diverge completely. This suggests that the conserved domain of the rel related family of proteins performs a common function that is modulated by the carboxyl terminal domain.