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J F Mushinski

Publications and source records attributed to J F Mushinski.

143 records · Page 8Linked to original sources
PubMed1980

Mouse immunoglobulin D: construction and characterization of a cloned delta chain cDNA.

TEPC 1017 is a BALB/c plasmacytoma that synthesizes IgD in large enough amounts to permit the isolation of mRNA for mouse delta chains. cDNA has been prepared from this mRNA, and an 880-base-pair fragment of it has been cloned by recombinant DNA techniques. The hybridization selection technique has been used to show that this cDNA clone specifically binds only mRNA that can be translated into immunoprecipitable delta chains. the sequence of a portion of this clone has been determined and, when translated, shows homology with the C delta 3 of a human myeloma protein. Using this cDNA clone as a probe, we have found that several different-sized delta RNAs are present in TEPC 1017 and in another IgD-secreting plasmacytoma, TEPC 1033.

Animals↗
PubMed1979

Transfer ribonucleic acids from eleven immunoglobulin-secreting mouse plasmacytomas. Constant and variable chromatographic profiles compared with the myeloma protein sequences.

In order to test the concepts that aminoacyl-tRNAs in plasmacytomas may on the one hand modulate the protein synthesized or on the other hand reflect the structure of the synthesized protein, the RPC-5 chromatographic profiles of aminoacyl-tRNAs for all 20 amino acids were studied in tRNA prepared from normal mouse liver and 11 plasmacytomas. The patterns of isoaccepting tRNA were compared with the structure of the myeloma protein being synthesized. The elution profiles of aminoacyl-tRNAs for nine of the amino acids were constant, i.e. they were the same for liver and all plasmacytomas. Significant variability was observed in the profiles of the other 11 families of aminoacyl-tRNAs: asparagine, serine and tryptophan, had peaks of isoaccepting tRNAs found in tumors and not in liver; glutamic acid, histidine and lysine, had different patterns of aminoacyl-tRNAs in plasmacytomas which could be distinguished from the elution profile of liver; and isoleucine, proline, threonine and tyrosine, showed pattern variability in only a few of the tumors. Valyl-tRNA uniquely had one isoacceptor present in liver but absent in the tumors. This variability is thought to be associated with different posttranscriptional modification of the tRNAs rather than regulation of individual tRNA genes in response to particular amino acid sequences in secreted myeloma proteins. Similarily, the lack of correlation of isoacceptors with sequence differences makes the modulation of protein fine structure by tRNA availability unlikely.

Amino Acid Sequence↗
PubMed1979

Biochemical changes induced by tumors at distant sites: altered transfer RNA profiles in livers of mice bearing plasmacytomas.

Tumor growth is known to have systemic effects upon the host's metabolism. We report here for the first time that histologically normal livers of mice bearing subcutaneous plasmacytomas contain chromatographic peaks of asparaginyl-, aspartyl-, histidinyl-, and tyrosinyl-transfer RNAs not found in significant amounts in normal livers. Lysyl-, prolyl-, seryl-, threonyl-, tryptophanyl-, and valyl-transfer RNAs, from normal tissues, but these tRNAs are not altered in livers of tumor bearing mice. This suggests that distant tumor growth causes a derangement in one of the liver enzymes that normally modify transfer RNA after transcription.

Animals↗
PubMed1979

Tumor-associated phenylalanyl transfer RNA found in a wide spectrum of rat and mouse tumors but absent in normal adult, fetal, and regenerating tissues.

RPC-5 chromatography was used to examine the phenylalanyl transfer RNA (Phe-tRNA) of 25 normal rat and mouse tissues including adult, fetal, and regenerating liver; whole embryos; and other adult organs. Only a single major isoaccepting Phe-tRNA was found in every case. Phe-tRNA's from 25 transplantable rat tumors and 33 transplantable mouse tumors were similarly examined. Seventeen rat tumors and 10 mouse tumors, of a wide spectrum of histological types, were found to have an additional, tumor-associated Phe-tRNA isoacceptor. This tumor-associated Phe-tRNA was not found in the livers of animals bearing tumors that contained this isoacceptor. Differences in chromatographic behavior between the rat and mouse tumor-associated Phe-tRNA's strongly suggest that they have different structures. Our data suggest that these differences result from different degrees of incompleteness of posttranscriptional modification, most likely at the normally very hypermodified Wye (formerly called Y) base.

Animals↗
PubMed1977

Multiple chromatographic peaks of phenylalanyl-tRNA associated with spontaneous hydrolysis of Y base during isolation.

In contrast to the single phenylalanyl-tRNA found in normal cells, some tumours are known to have more than one phenylalanine isoacceptor. However, during certain steps in tRNA isolation from normal or tumour tissue, additional chromatographic peaks can be artificially produced which may be confused with the tumour-specific Phe-tRNA. Such procedures as extraction with unbuffered phenol and unbuffered gel filtration chromatography appear to produce adventitious isoacceptors by hydrolysis of Y base.

Animals↗
PubMed1976

IgA half molecules. II. Genetic variants of IgA detected in normal mouse intestinal contents.

Six two chain IgA myeloma proteins are found to have very similar molecular weights and to share immunochemical characteristics suggesting that they represent examples of an unusually small-sized variant of normal mouse IgA. With the use of homologous antiserums in 2-dimensional double diffusion and hemagglutination inhibition, small amounts of this unusual IgA were detected in normal BALB/c intestinal contents. Gel filtration of the intestinal contents suggests that these gut immunoglobulins A exist in a size consistent with a single light chain plus a single heavy chain and can be regarded as IgA "half molecules" or IgAb. We feel that IgAb represents a normal variant of mouse IgA, but the possibility of its being a second mouse IgG subclass is discussed.

Animals↗
PubMed1968

2-chain immunoglobulin A molecules: abnormal or normal intermediates in synthesis.

Immunoglobulin A (gammaA) myeloma proteins secreted by plasma-cell tumors of mice are of two types, a common four-chain molecule and a rare two-chain (3.9S) molecule. The close similarity between two-chain gammaA molecules and four-chain gammaA molecules and their polymers is demonstrated in tryptic peptide maps of isolated polypeptide chains and by precipitin reactions with rabbit antiserums to gammaA immzunoglobulins. However, a difference between these two types is distinguishable with homologous antiserums. Homologous antiserums to two-chain gammaA immunoglobulins are specific and do not cross-react with four-chain gammaA immutnoglobulins.

Animals↗