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Biomedical subjects

B K Pal

Publications and source records attributed to B K Pal.

12 recordsLinked to original sources
PubMed1978

RNA tumor virus phosphoproteins: primary structural analysis and identification of phosphopeptides.

Two-dimensional tryptic peptide mapping was used to compare the peptide sequences of the phosphoprotein (pp12) of cloned ecotropic and amphotropic wild mouse leukemia viruses, strains 1504 and 292. The maps of two ecotropic isolates were very similar to one another, as were the maps of two amphotropic isolates. There was also extensive similarity between the maps of this protein from ecotropic and amphotropic viruses, although characteristic peptide differences were readily recognized. These differences were consistent with the general type specificity of oncovirus phosphoproteins. The pp12 of the field isoalte of 292 virus contained five phosphopeptides, and the non-phosphorylated and variously phosphorylated species of this pp12 showed identical peptide maps, indicating differential phosphorylation of a single polypeptide.

Base Sequence↗
PubMed1976

Assay for type C virus in mouse sera based on particulate reverse transcriptase activity.

Assay of particulate reverse transcriptase activity in the sera from feral mice naturally infected with type C virus provides a sensitive and rapid procedure for the determination of in vivo virus infection. The results compare well with assays for infectious virus and with complement fixation or competitive radio-immunoassays for the p30 internal antigen of the virus.

Animals↗
PubMed1975

Phosphoproteins: structural components of oncornaviruses.

Oncornaviruses, which contain a virion-associated protein kinase, were found to possess phosphoproteins as virion structural components. One major phosphoprotein common to strains of laboratory and wild mouse oncornaviruses and a strain of feline leukemia virus was shown to be a polypeptide of about 12, 000 mol wt. In addition to this, the Kirsten strain of murine sarcoma virus contained a second major phosphoprotein of about 10, 000 mol wt, and mouse erythroblastosis virus contained a second major phosphoprotein that was either identical to or comigrated with the virion glycoprotein of about 74, 000 mol wt. The major phosphoprotein of RD-114 virus was found to be of about 16, 000 mol wt. The major phosphoamino acid of the 12, 000-mol wt polypeptide of the mouse erythroblastosis virus was identified as phosphoserine, and that of the 16, 000-mol wt polypeptide of the RD-114 virus was identified as phosphothreonine.

Electrophoresis, Paper↗
PubMed1975

Comparative studies on the structural phosphoproteins of mammalian type C viruses.

The major phosphoprotein common to woolly monkey sarcoma virus, gibbon ape lymphosarcoma virus, and type C viruses of the lower mammalian species (mouse, rat, cat), with the exception of the endogenous cat virus (RD-114), is the polypeptide of about 12,000 molecular weight. The protein-phosphate bond in this polypeptide of several viruses is of the phosphoserine variety excepting gibbon ape virus, which contains both phosphoserine and phosphothreonine. The primary phosphoprotein of RD-114 virus and the endogenous baboon type C virus, on the other hand, is the polypeptide of about 15,000 molecular weight which contains phosphothreonine as its phosphoamino acid. A second major phosphoprotein of molecular weight of 10,000 is detected only in viruses genetically related to rat species including those derived from the RPL cell line, from Sprague-Dawley rat embryo cells, and the Kirsten mouse sarcoma virus which was recovered from a mouse erythroblastosis virus after in vivo propagation through rat. These phosphorylated polypeptides of molecular weight 15,000, 12,000, or 10,000 are present in the virion structure in several different but nonrandom phosphorylated states.

Animals↗
PubMed1975

Biochemical properties of wild mouse oncornaviruses with lymphomagenic and neurotropic activities.

The close immunologic relation between the group-specific and polymerase proteins of the wild mouse derived and the established strains of mouse type C oncornaviruses, and the lack of any unusual structural polypeptide or RNA components in the wild mouse virions, eliminate the possibility of detectable contamination by a class of virus different from the mouse oncornavirus class in the wild mouse virus preparations. Liquid hybridization studies with a wild mouse viral 70S 3H-RNA and cellular DNA under conditions of DNA excess, suggest that a significant fraction but not all of the virus-specific nucleotide sequences is present in all normal and tumored wild mouse tissues tested. These virus related sequences may possibly be attributed to a hypothetical endogenous inherited type C virus genome(s) carried by all wild mice or to an infection by one or more but not all of the different exogenous strains of wild mouse type C viruses which could possibly be present in the virus preparation used. The findings are consistent with wild mouse derived type C viruses being either entirely exogenous or a mixture of endogenous and exogenous viruses. This interpretation is also consistent with the earlier observation that certain wild mouse type C viruses are exogenously transmitted, transplacentally, and via milk. The possible relation of the virus heterogeneity or the distinct characteristics of the virus surface molecules to the diverse pathogenicity of the wild mouse oncornaviruses is discussed.

DNA Nucleotidyltransferases↗