Tryptic peptide analysis of gag and gag-pol gene products of Rauscher murine leukemia virus

Publisher Website
Google Scholar
Abstract
[3H]tryosine-labeled viral precursor polyproteins and known mature viral proteins derived from the Rauscher murine leukemia virus gag and pol genes were examined by 2-dimensional tryptic peptide mapping. Pr200gag-pol contained peptide sequences of the viral core proteins p30, p15, p12 and p10 and peptide sequences found in the cell-associated reverse transcriptase. Intermediate reverse transcriptase precursor Pr125pol lacked peptide sequences of the 4-core proteins but contained reverse transcriptase-specific tryptic peptides plus 2 additional tyrosine-containing tryptic peptides not related to gag or pol gene products. Methionine-containing tryptic peptide analysis also suggested the presence of additional protein material in Pr125pol. Pr200gag-pol contained both viral core and reverse transcriptase-associated methionine, tyrosine tryptic peptides and additional tryptic peptides. These are of 2 classes: tryptic peptides associated with the Pr125pol but not Pr80pol and tryptic peptides not found in Pr125pol or in any known viral protein. Pr200gag-pol may contain additional gene products aside from the gag and pol genes. Pr80gag and Pr65gag peptide maps were examined and had sequences of all 4 core proteins. Pr65gag contained 2 p30 tyrosine tryptic peptides that were absent in Pr80gag; Pr80gag may not be the precursor to Pr65gag. Pr80gag, as expected from its larger size, also contained tryptic peptides not found in Pr65gag. Two additional Pr80gag tryptic peptides were also found in Pr80pol but not in any of the viral core proteins; Pr80gag and Pr80pol may have overlapping peptide sequences. Pr80gag apparently terminates within the pol gene. A model that describes the relationship of these recent findings to viral gene products is presented.