Complete c-mos (rat) nucleotide sequence: presence of conserved domains in c-mos proteins

Recently we described the isolation of c-mos (rat). The gene belongs to the family of oncogenes. Some facts render c-mos unique among the oncogenes : a) it does not contain intervening sequences and b) its expression was never detected in a large number of normal mouse tissues examined. We undertook the sequence analysis of c-mos (rat) in order to compare it to the nucleotide sequences published for c-mos (mouse), c-mos (human), c-src and bovine protein kinase. c-mos (rat) contains an open reading frame of 1017 nucleotides, coding for a polypeptide of 339 amino acids. c-mos (rat)-makes use of the same ATG that defines the N-terminus of the c-mos (human) protein. By comparing all c-mos sequences available we found sequences with high mutational rates to be confined to certain domains. This comparison, together with data on the biological activities of the cloned DNA, allowed us to tentatively define regions involved in (a) function(s) of c-mos other than transformation.     

Molecularly cloned c-mos(rat) is biologically active.

A unique rat cellular gene, c-mos(rat), homologous to the transforming sequences, v-mos, of Moloney murine sarcoma virus (M-MSV) was detected by hybridization to a v-mos specific probe. The c-mos(rat) gene was cloned together with its flanking sequences in an 11-kbp EcoRI DNA fragment inserted in vector Charon 4A. Two probes were used to investigate the position and orientation of c-mos(rat) in the clone examined ( D3e ), namely pMSV -31 which contains the sequences specific for the transforming sequences of M-MSV and pCS-1 which harbors 0.5 kbp of 5'-terminal sequences of c-mos(mouse) as well as 0.7 kbp of its flanking sequences. After ligation of a restriction fragment of clone D3e containing c-mos(rat) to a fragment containing the long terminal repeat of M-MSV and transfection of the DNA onto rat cells, we detected foci of transformed cells, thus showing that c-mos(rat) is biologically active. Using DNA framents derived from clone D3e , we studied the conservation of c-mos and of its flanking sequences in several species. c-mos(rat) as well as some of its flanking sequences appeared to be highly conserved in the species studied.