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M B Roth

Publications and source records attributed to M B Roth.

28 records · Page 2Linked to original sources
PubMed1993

Human SR proteins and isolation of a cDNA encoding SRp75.

SR proteins are a family of proteins that have a common epitope recognized by a monoclonal antibody (MAb104) that binds active sites of polymerase II transcription. Four of the SR family members have been shown to restore activity to an otherwise splicing-deficient extract (S100 extract). Here we show that two untested SR proteins, SRp20 and SRp75, can also complement the splicing-deficient extract. We isolated a cDNA encoding SRp75 and found that this protein, like other SR proteins, contains an N-terminal RNA recognition motif (RRM), a glycine-rich region, an internal region homologous to the RRM, and a long (315-amino-acid) C-terminal domain composed predominantly of alternating serine and arginine residues. The apparent molecular mass of dephosphorylated SRp75 is 57 kDa, the size predicted from the cDNA clone. We also detected mobility shifts after dephosphorylating SRp55, SRp40, SRp30a, and SRp30b; the sizes of the shifts are proportional to the length of the SR domain, suggesting that serines in this domain are phosphorylated.

Amino Acid Sequence↗
PubMed1992

Two members of a conserved family of nuclear phosphoproteins are involved in pre-mRNA splicing.

Monoclonal antibody 104 recognizes a subset of amphibian nuclear granules (B-snurposomes) and active sites of RNA polymerase II transcription in vertebrates and invertebrates. Monoclonal antibody 104 reacts with a set of nuclear serine- and arginine-rich phosphoproteins (SR family) with strikingly conserved apparent molecular masses. The most abundant family members in human (SRp33) and Drosophila (SRp55) cell lines can replace one another as essential splicing factors in a human cell-free system. Each of these polypeptides can functionally replace human SF2, an essential splicing factor that also regulates 5' splice site selection of alternatively spliced pre-mRNAs in vitro. Drosophila SRp55 also functions as an alternative splicing factor in the human cell-free system. Analysis of cloned cDNAs shows that SRp55 and SF2 are highly related and reveals regions of similarity to genetically defined regulators of alternative splicing in Drosophila. These results suggest that the conserved SR family of phosphoproteins, which includes SRp55 and SF2, is involved in constitutive pre-mRNA splicing and in the specificity of alternative splice site selection.

Amino Acid Sequence↗
PubMed1992

SR proteins: a conserved family of pre-mRNA splicing factors.

We demonstrate that four different proteins from calf thymus are able to restore splicing in the same splicing-deficient extract using several different pre-mRNA substrates. These proteins are members of a conserved family of proteins recognized by a monoclonal antibody that binds to active sites of RNA polymerase II transcription. We purified this family of nuclear phosphoproteins to apparent homogeneity by two salt precipitations. The family, called SR proteins for their serine- and arginine-rich carboxy-terminal domains, consists of at least five different proteins with molecular masses of 20, 30, 40, 55, and 75 kD. Microsequencing revealed that they are related but not identical. In four of the family members a repeated protein sequence that encompasses an RNA recognition motif was observed. We discuss the potential role of this highly conserved, functionally related set of proteins in pre-mRNA splicing.

Amino Acid Sequence↗
PubMed1991

A conserved family of nuclear phosphoproteins localized to sites of polymerase II transcription.

An antibody was identified previously that recognizes sites of polymerase II transcription on lampbrush chromosomes, puffs on polytene chromosomes, and many small granules in the nucleoplasm of all cells tested. This antibody binds a conserved family of phosphorylated polypeptides in vertebrate and invertebrate cells. We developed a method for purifying these proteins that involves differential solubility in MgCl2. We isolated a Drosophila cDNA encoding one of the proteins using information obtained from microsequencing. In vivo expression studies show that this protein is concentrated on sites of polymerase II transcription and that it is highly phosphorylated. The protein shares a high degree of homology with proteins involved in alternative splicing of pre-mRNA suggesting the possibility that this protein plays a role in pre-mRNA splicing.

Amino Acid Sequence↗
PubMed1990

A monoclonal antibody that recognizes a phosphorylated epitope stains lampbrush chromosome loops and small granules in the amphibian germinal vesicle.

An mAb library was produced against proteins from the germinal vesicle (GV) of the frog Xenopus laevis; mAb 104 was selected from this library on the basis of its immunofluorescent staining of lampbrush chromosome loops. Chromosomes from several species of frogs and salamanders stained equally well. The antibody also stained the surface of numerous small granules in the GV nucleoplasm. The interior of the same granules was stained by antibodies against small nuclear ribonucleoproteins (snRNPs). mAb 104 also stained somatic nuclei from many vertebrate and invertebrate species, usually in a finely punctate pattern similar to that described for anti-snRNP and other antinuclear antibodies. The staining of somatic nuclei was much stronger during the mitotic stages than during interphase. Immunoblot analysis showed that mAb 104 recognizes a phosphorylated epitope.

Animals↗
PubMed1989

Targeting of a chromosomal protein to the nucleus and to lampbrush chromosome loops.

We have isolated a cDNA clone (SE5A) that encodes a protein on lampbrush chromosome loops of the newt Notophthalmus. In vitro-synthesized transcripts of this clone were injected into Xenopus oocytes, where they were efficiently translated. Most of the translated protein was imported into the oocyte nucleus, and some of it appeared on the chromosome loops. The translation product must contain information that permits its appropriate targeting first to the nucleus and then to the chromosome loops.

Amino Acid Sequence↗
PubMed1987

Monoclonal antibodies that recognize transcription unit proteins on newt lampbrush chromosomes.

We prepared hybridoma cell lines from mice injected with newt germinal vesicle proteins. We tested culture supernates from these cell lines for antibodies that bound to specific morphological structures in lampbrush chromosome preparations (nucleoli, loops, chromomeres, etc.). Four mAbs that recognize antigens on the lateral transcription loops are described here. We suggest that these antigens are proteins associated with nascent RNA transcripts, although they are not among the 30-40-kD "core" heterogeneous nuclear ribonucleoproteins.

Animals↗
PubMed1979

Alleles of the fibroin gene coding for proteins of different lengths.

Bombyx mori silkworms producing fibroin proteins of different lengths have been analyzed genetically and shown to possess variant alleles of a single fibroin gene. The structures of two alleles have been compared by using restriction endonuclease sites inside and outsite the fibroin gene as physical markers. We find that fibroins distinguishable on the basis of length are encoded by genes with different internal structures and overall lengths. Our results strongly support the idea that rearrangements within the highly repetitive sequences of the fibroin gene are the result of unequal recombination, and can give rise to variant fibroin genes with altered coding lengths.

Alleles↗
PubMedDate not supplied

Canine parvovirus vaccine elicits protection from the inflammatory and clinical consequences of the disease.

Inflammatory changes following infection are central to the clinical manifestation of disease. However, information regarding such changes in animal disease is limited. In canine parvovirus infected puppies we measured the levels of acute phase proteins and changes in leukocyte phenotypes and cell trafficking by flow cytometry. These parameters correlated with conventional assessment of clinical disease in a vaccine efficacy study. Seropositive (CPV-2) 6-week-old puppies given three doses of a CPV-2 containing vaccine developed significant antibody titers and remained healthy after experimental infection with CPV-2b. Unvaccinated controls developed clinical signs and shed virus. Importantly, acute phase proteins became elevated, and lymphopenia, neutropenia and modulation of neutrophil-CD4 were detected in controls but not in vaccinates.

Animals↗