Markedly elevated levels of an endogenous sarc protein in a hemopoietic precursor cell line.
The src gene product of Harvey murine sarcoma virus is a 21,000-dalton guanine nucleotide-binding protein. We have recently shown that a wide variety of vertebrate cell strains and cell lines express much lower levels of an endogenous p21 immunologically related to the Harvey murine sarcoma virus-coded p21. In this report, we have examined the levels of endogenous p21 in a unique hemopoietic precursor cell line, 416B, which was originally described as a continuous cell line of a hemopoietic stem cell, CFU-S. The currently available 416B cells express markedly elevated levels of endogenous p21. The level of endogenous p21 in the 416B cells is 5- to 10-fold higher than the level of p21 in Harvey murine sarcoma virus-infected cells and more than 100 times higher than the level of endogenous p21 that we have observed in a variety of other fresh or cultured cells. The results indicate that marked regulation of the levels of an endogenous sarc gene product can occur, and speculation about a possible role for endogenous p21 in normal hemopoietic stem cells is discussed.
D000818:Animals; D002461:Cell Line, Transformed; D004279:DNA, Viral / Q000235:genetics / Q000302:isolation & purification; D019204:GTP-Binding Proteins / Q000378:metabolism; D005814:Genes, Viral; D006251:Harvey murine sarcoma virus / Q000235:genetics / Q000378:metabolism; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D015689:Oncogene Protein p21(ras); D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000378:metabolism*
D004279:DNA, Viral; D009856:Oncogene Proteins, Viral; D019204:GTP-Binding Proteins; D015689:Oncogene Protein p21(ras)