LSUHSC research finds evidence of RNA in structures essential to cell division

Research led by Mark Alliegro, PhD, Professor of Cell Biology and Anatomy at Louisiana State University Health Sciences Center at New Orleans, provides evidence for the first time that centrosomes, which play a key role in cell division, may carry their own genetic machinery, answering a controversial question of long standing. Dr. Alliegro found five RNA sequences that appear to be unique to the centrosome. The discovery, providing new insight into centrosome function, heredity, and evolution is published in today's issue of Proceedings of the National Academy of Sciences. The research team included Mary Anne Alliegro, a Research Associate at LSU Health Sciences Center at New Orleans, and Robert Palazzo, PhD, Professor of Biology and Director of the Center for

Biotechnology and Interdisciplinary Studies at Rensselaer Polytechnic Institute. The research was conducted at the Marine Biological Laboratory in Woods Hole, MA.

Studying surf clam eggs, the research team focused on centrosomes, small areas of cytoplasm that serve an organizational purpose which not only assures proper cell division, but also genetic stability. The most recent review of the question of whether or not centrosomes contain nucleic acids concluded that there is no evidence of DNA, but the presence of RNA, although controversial, was still an open question. RNA is the nucleic acid that governs protein synthesis as well as the transmission of genetic material.

Using a technique he developed, Dr. Palazzo isolated relatively large quantities of centrosomes from the clam eggs. The Alliegros, using highly sophisticated techniques they developed, extracted a set of RNAs called cnRNAs, demonstrating their association with centrosomes biochemically and in situ. Exhaustive database analysis revealed no matches to known nucleotides, translated nucleotide, or predicted protein sequences, founding the conclusion that they are unique and intrinsic to the centrosome.

"The implications are broad and I expect there will be lively discussion on their meaning for topics from cell division to eukaryotic evolution," says Dr. Mark Alliegro. "At this point we know very little about their function or origins, but we are confident they represent a special set of transcripts."

Centrosome irregularities have been linked to malignancies, so the discovery may also be applicable to cancer research.

"The next step will be to determine what role these RNAs might play in centrosome replication, the cell cycle, or the development of organisms," concludes Dr. Alliegro.

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