Mark Alliegro,
Senior Research Scientist

Mark Alliegro's CV>>

Alliegro Lab Personnel>>

The modern eukaryotic cell is derived from its ancestors both by direct filiation (accumulation of random mutations) and by symbiogenesis. In symbiogenesis, one cell, internalized by another, persists in the cytoplasm as an obligate relationship develops. Through mutation, lateral gene transfer, and selective processes, the fused individuals become interdependent. This is how eukaryotic cells came to have mitochondria and chloroplasts. Some scientists postulate that the cell motility system, or at least parts of it, were also derived exogenously, by symbiogenesis. Especially because of its mode of duplication and cytoplasmic inheritance, the centriole, centrosome, and related structures have long been at the center of evolutionary debate. If any exogenous model for the origin of the centriole-centrosome is true, then one would predict at least remnants of a genome to be associated with the organelle. Using centrosomes isolated from oocytes of the surf clam, Spisula solidissima, we have extracted and cloned a unique library of RNAs. These centrosome-associated RNAs (cnRNAs) co-isolate with centrosomes, are biochemically enriched in the centrosome fraction of cells, localize with the centrosome in situ, and exhibit structural features at variance with other, previously characterized Spisula genes. Our long term goals are to identify the functions of cnRNAs and determine if they represent an organellar genome as has been described for mitochondria and chloroplasts.

Recent Publications:

Alliegro, M.C. and M.A. Alliegro 2005. Differential expression of tyrosinated tubulin in Spisula solidissima polar bodies. Dev. Dyn., 232:216-221.

Alliegro, M.C., Alliegro, M.A., and R.E. Palazzo 2006. Centrosome-associated RNA in surf clam oocytes. Proc. Nat'l. Acad. Sci. U.S.A., 103:9034-9038.

Chapman, M. and M.C. Alliegro 2007. A symbiogenetic origin for the centrosome? Symbiosis, 44:23-31.

Alliegro, M.C. and M.A. Alliegro 2007. Echinonectin is a Del-1—like molecule with regulated expression in sea urchin embryos. Gene Expr. Patterns 7:651-657.

Alliegro, M.C. and M.A. Alliegro 2008. Centrosomal RNA correlates with intron-poor nuclear genes in Spisula oocytes. Proc. Nat'l. Acad. Sci. U.S.A. 10.1073/pnas.0802293105.

Alliegro, M.C. and M. Chapman. The Karyomastigont seme. In preparation.