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S Damjanovski

Publications and source records attributed to S Damjanovski.

3 recordsLinked to original sources

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

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