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M Ringuette

Publications and source records attributed to M Ringuette.

6 recordsLinked to original sources
PubMed1992

Molecular analysis of Xenopus laevis SPARC (Secreted Protein, Acidic, Rich in Cysteine). A highly conserved acidic calcium-binding extracellular-matrix protein.

SPARC (Secreted Protein, Acidic, Rich in Cysteine) is expressed as a 1.6 kb mRNA in Xenopus laevis. On the basis of cDNA sequence analysis, Xenopus SPARC has a core Mr of 32643, with one potential N-glycosylation site. Western analysis of SPARC isolated from Xenopus long bone indicates that the mature protein has an Mr of 43,000. At the amino acid level, Xenopus SPARC has 78-79% sequence similarity to mouse, bovine and human SPARC. The least-conserved region is found within the N-terminal glutamic acid-rich domain, with the C-terminal Ca(2+)-binding domain being the most conserved. Adult Xenopus tissues show the same pattern of tissue-specific distribution of SPARC mRNAs as adult mouse.

Amino Acid Sequence↗
PubMed1992

Cytoplasmic localization of the DNA virus frog erythrocytic virus.

In situ hybridization, using a biotinylated clone of frog erythrocytic virus (FEV), was conducted to determine the location of viral sequences in bullfrog erythrocytes. FEV-specific hybridization signals were found to correspond to mature cytoplasmic viral particles and assembly sites. These data are consistent with electron microscopic observations of viral assembly in the erythrocyte cytoplasm. Although FEV has morphological and biochemical properties similar to frog virus 3, our data suggest that the site of DNA replication and assembly of FEV is more similar to that of the poxviruses.

Amino Acid Sequence↗
PubMed1991

Expression of SPARC/osteonectin in tissues of bony and cartilaginous vertebrates.

To explore the biological functions of SPARC (secreted protein, acidic, rich in cysteine), a Ca(2+)-binding extracellular glycoprotein, we have examined its expression in an evolutionary diverse group of organisms. Similar patterns of SPARC mRNA expression were observed in adult mouse and rat tissues. SPARC transcripts represented 0.0002-0.0025% of the total RNA found in calvarium, lung, brain, and heart, whereas relatively low levels of SPARC RNA were detected in liver and kidney. Within nonmuscular tissues, a statistically significant correlation was observed between the tissue distribution of SPARC and cytoskeletal actin transcripts. Southern blot analysis revealed SPARC as a low or single-copy gene in an evolutionary diverse group of vertebrates. No hybridization signal was observed with the invertebrates examined. The tissue distribution of SPARC transcripts in the vertebrates examined was similar, except for sea lamprey and sea skate, two vertebrates that do not form mineralized bone. These data suggest that SPARC has multiple functions in mineralized and nonmineralized tissues of vertebrates.

Actins↗
PubMed1987

Localization of Escherichia coli RNA polymerase-binding sites on bacteriophage S13 replicative form I DNA by protection of restriction enzyme cleavage sites.

Protection of restriction endonuclease cleavage sites by Escherichia coli RNA polymerase bound to the replicative form I of bacteriophage S13 DNA has been used to identify a number of regions of RNA polymerase binding. Digestion with HincII, AluI, HinfI, or HaeIII, under conditions optimized for "open" complex formation, revealed 12 regions of RNA polymerase binding. Based on differential salt sensitivities, five of the regions were classified as strong or tight binding sites. These were located before genes A (two sites), B, and D and at the 5' end of gene F. The seven regions which exhibited weaker binding were located at the 5' end of gene C (two sites), in the middle of gene D, just before and at the 3' end of gene F, at the 5' end of gene G, and in the middle of gene H. The sites before genes B and D coincide with sites previously identified as promoters in bacteriophage phi X174. One of the sites before gene A, that at nucleotides 5175-5211, represents a new putative promoter site in bacteriophage S13 and phi X174 located before the previously identified A gene promoter at nucleotides 10-45.

Base Sequence↗