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H L Niman

Publications and source records attributed to H L Niman.

27 records · Page 2Linked to original sources
PubMed1980

Chemical synthesis of a polypeptide predicted from nucleotide sequence allows detection of a new retroviral gene product.

We previously determined the nucleotide sequence of the 3' end of Moloney leukaemia virus and discovered the potential coding region for an unknown protein, R. We now show that this region does encode a protein. A pentadecapeptide of R was chemically synthesized and antibodies raised against it. Antisera to the synthetic peptide recognize the R protein and the env precursor polyprotein in infected cells. The strategy presented here should provide a general method for accessing proteins predicted by nucleotide sequences.

Amino Acid Sequence↗
PubMed1980

Molecular dissection of Rauscher virus gp70 by using monoclonal antibodies: localization of acquired sequences of related envelope gene recombinants.

Using hybridoma-specific immune precipitations of fragments derived from Rauscher virus gp70, coupled with peptide patterns (fingerprinting) and partial amino acid sequence analyses, we have generated a linear map of Rauscher gp70. We used a panel of 56 hybridomas derived from the fusion of the drug-selected SP-2 myeloma line with spleen cells from either a 129 GIX+ or a GIX- mouse immunized with purified Rauscher virus gp70. The results showed that by "natural" breakdown, gp70 splits into predominant fragments, with Mr 45,000 (P45), 34,000 (P34), and 32,000 (P32). Peptide fingerprinting of these as well as overlapping fragments coupled with partial amino acid sequence analyses allowed us to align the fragments into the linear arrangement NH2-P45-P32-COOH, with P34 being an NH2-terminal degradation product of P45. Of the 56 hybridomas, 20 immunoprecipitated both P45 and P34; 18 immunoprecipitated only P45; and 18 immunoprecipitated only P32. The hybridomas thus define three domains of the molecule as NH2-P45/P34, P45 only, and P32-COOH. Allowing these hybridomas to react with two Rauscher-derived envelope gene recombinant viruses yielded the following results: (i) all 20 P45/34 reactors bound to the two Rauscher recombinants; (ii) of 18 P45-only hybridomas, 10 reacted; and (iii) only 1 of 18 P32 reactors bound to the Rauscher recombinants. This last hybridoma reacted with various murine retroviruses, indicating that it was directed at conserved determinants of gp70. Peptide fingerprinting of R-gp70, the recombinant gp70s, and their respective breakdown products confirmed the homologies and nonhomologies defined by the hybridomas. Furthermore, peptide patterns showed that these acquired sequences on the COOH-terminal portion of the recombinant gp70s are related to xenotropic virus gp70s.

Amino Acid Sequence↗
PubMed1977

Endogenous RD-114 virus genome expression in malignant tissues of domestic cats.

Endogenous xenotropic cat type C virus (RD-114)- and infectious feline leukemia virus (FeLV)-specific gene expressions were measured in spontaneous sarcomas carcinomas, and nonmalignant cat tissues by molecular hybridization for virus-specific RNA and competition radio-immunoassays for the major internal protein (p30) of these two viruses. The results indicate that RD-114 gene expression in sarcomas and carcinomas at both RNA and p30 levels is significantly higher than histologically normal tissues from cats free of cancer. In contrast, the levels of FeLV viral RNA and p30 are fount to be low or undetectable in the majority of these tumored and normal tissues examined. Whereas variability in the amounts of RD-114 OR FeLV RNA and p30 expressed is found in tissues from different cats, their expression is fairly uniform in multiple malignant tissues of the same cat. The finding of widespread occurrence of elevated RD-114 gene expression in sarcomas and carcinomas is consistent with our similar observation with natural lymphomas of domestic cats and suggests that expression of certain functions of this endogenous virus may be etiologically involved in the development of many different spontaneous neoplasms of cats.

Animals↗
PubMedDate not supplied

Antisera to a synthetic peptide of the sis viral oncogene product recognize human platelet-derived growth factor.

It has recently been reported that the sequences of the sis oncogene of simian sarcoma virus (SSV) and of human platelet-derived growth factor (PDGF) are very similar, establishing the most solid link yet between the mitogenic actions of growth factors and the transforming proteins of retroviruses. To investigate molecular mechanisms of transformation I have produced antisera against synthetic peptides corresponding to segments of the protein sequences predicted by the nucleotide sequences of viral oncogenes. Applying this approach to the case of sis and PDGF, I report here the results of probing outdated human platelets with an antiserum directed against a synthetic peptide representing residues 139-155 of the predicted sequence of the SSV transforming protein, p28sis (ref. 3). I detected peptides of apparent molecular weights (MWs) 30,000 to 31,000 (30-31K) and 16-18K, which correspond to the apparent molecular weights of nonreduced and reduced PDGF. In addition, a peptide of MW 21,000 was detected in platelets and a protein of MW 56,000 was detected in SSV-infected marmoset cells.

Amino Acid Sequence↗
PubMedDate not supplied

Evaluation of oncogene-related proteins in serum.

We hypothesize that the products of cellular oncogenes and antioncogenes are biomarkers of events related to cancer risk. This study uses monoclonal antibody technology to examine serum proteins which are immunologically related to ras oncogene and epidermal growth factor receptor proteins. We measured the prevalence of ras- and epidermal growth factor receptor-related proteins in stored and freshly frozen serum from cancer patients, male heavy smokers, and older healthy subjects. Work emphasized the attainment of inter- and intraobserver agreement between independent readings of immunoblot gels. Although we achieved acceptable levels of agreement, we uncovered evidence for blood collection and storage artifacts. Accounting for these artifacts, we compared 80 cancer patients and 188 middle-aged and older community controls and found a strong relationship (odds ratio = 11.1; 95% confidence interval, 6.0-20.6) between cancer and a M(r) 21,000 serum protein related to the ras oncogene product. These results indicate the need and importance of comprehensive pretesting of putative cancer biomarkers before use in applied or etiological epidemiological research.

Antibodies, Monoclonal↗