Evidence for somatic cell expression of the c-mos protein [corrected].
The c-mos protein has been found to be enriched in germ cells of male mice, as described in a recent report from this laboratory (Herzog et al., Oncogene 3, 225, 1988). We report on further studies which indicate that the c-mos protein (a 41 to 43 kDa protein termed p43c-mos) is expressed in somatic tissues of mice and in cells grown in culture. In testes of mice, germ cell fractions have increased levels of p43c-mos relative to other cells of the testes. However, non-germ cells harbor significant levels of p43c-mos, as judged by comparison of testes from normal mice to those with mutations that affect the germ cell content of the testes. Thus, homozygous S1, at, and the W/Wv mutant mice are sterile due to severe deficiencies of germ cells. Such mice had only an estimated 50%-60% reduction in p43c-mos as judged by western immunoblotting using two different site-directed anti-mos antibodies. Similarly, X/X-sex reversed mice in which germ cells die after 10 days of age had only an 85% reduction of p43c-mos in mice 35 days of age. Thus, the germ cell content of testes did not correlated with p43c-mos levels in this tissue. Direct analyses of non-germ cells derived from mouse testes confirmed these findings, since Sertoli and Leydig cell lines grown in culture expressed p43c-mos. In addition, tissues such as kidney, liver, spleen and brain were found to contain p43c-mos. Surprisingly, mouse NIH3T3 cells were found to express significant levels of the c-mos protein based upon immunoblotting and one-dimensional peptide mapping experiments performed with both anti-mos antibodies. The concentration of the c-mos protein was not affected by expression of viral mos proteins. We conclude that the c-mos protein is enriched in male germ cells, but p43c-mos is also expressed in significant amounts in somatic tissues and in fibroblastic cells grown in culture.
Herzog
N K
NK
Department of Molecular Pathology, University of Texas M.D. Anderson Cancer Center, Houston 77030.
Ramagli
L S
LS
Khorana
S
S
Arlinghaus
R B
RB
D000818:Animals; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D012734:Disorders of Sex Development; D015870:Gene Expression; D008297:Male; D051379:Mice; D008979:Moloney murine leukemia virus / Q000235:genetics; D010449:Peptide Mapping; D011505:Protein-Tyrosine Kinases / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000235:genetics*; D017231:Proto-Oncogene Proteins c-mos; D011519:Proto-Oncogenes; D012741:Sexual Maturation; D013091:Spermatogenesis; D013737:Testis / Q000201:enzymology*; D014158:Transcription, Genetic
D011518:Proto-Oncogene Proteins; D011505:Protein-Tyrosine Kinases; D017231:Proto-Oncogene Proteins c-mos