The findings, detailed June 5 in the online early edition of the journal Proceedings of the National Academy of Sciences, present evidence that individual centrosomes within a cell may carry their own genetic material.
"Our research provides direct biochemical evidence that RNA is present in the centrosomes of clam cells," says Robert Palazzo, professor of biology and director of the Center for Biotechnology and Interdisciplinary Studies at Rensselaer.
Palazzo's laboratory isolated clam centrosomes and Mark Alliegro and Mary Anne Alliegro of LSU Health Sciences Center analyzed the centrosomes for RNA content.
"Although the possibility of DNA inside the centrosome of the cell has been ruled out by others' previous work, the presence of RNA had not been confirmed or denied until now," says Palazzo. "Our results show there are at least five specific forms of RNA in the clam cell centrosome which could be related to structure, encoding of proteins, or the regulation of organism development. The specific role or function of the RNA in the centrosome and its possible involvement in the development of animals will be significant questions in continuing studies.
"Since RNA guides the translation of genes into proteins, knowing more about its role(s) in the centrosome may help researchers better understand the progression of diseases such as cancer, which has been linked to abnormal centrosome numbers in tumor cells," says Palazzo.
The study on surf clam centrosomes was initiated at the MBL, an international biological research center where scientists use locally abundant marine organisms like surf clams and their eggs as research models. Clam eggs are modeled as simple versions of human cells, and biologists who study cell division value them for several reasons, according to Palazzo. The eggs develop fast, entering the process of cell division less than 15 minutes after fertilization, and, once fertilized, divide in synch every 30-50 minutes -- providing billions of biochemically identical cells to study.
Using a purification technique Palazzo developed at the MBL, the scientists were able to isolate relatively large quantities of clam centrosomes for their research. Palazzo collaborated with Mark Alliegro and Mary Anne Alliegro during summers at the MBL.
In addition to his position as director of the Center for Biotechnology and Interdisciplinary Studies at Rensselaer, Palazzo also holds appointments at the MBL as visiting summer researcher and at the Wadsworth Center of the New York State Department of Health as research scientist.