Their findings are published online today at www.scienceexpress.org and will be published in an upcoming issue of the journal Science. Advance publication on scienceexpress.org typically indicates that the editors of Science want to get the information out in the public domain as soon as possible because of its importance.
The protein studied by the researchers is called E(Z). It belongs to a group of proteins known as Polycomb-group that may play an important role in turning other genes off during development. Some researchers believe Polycomb-group genes are involved in causing cancer, particularly some leukemias. This may happen when mutated versions of the genes fail to work properly, causing an overproliferation of blood cells or failing to make cells differentiate properly.
About 15 Polycomb-group genes have been discovered so far. The E(z) gene was discovered by Swedish researchers in 1974. Rick Jones, an associate professor of biological sciences at SMU, has been using genetic and molecular biological approaches to understand the activities of the E(z) gene and the protein it encodes since he was a postdoctoral fellow at Harvard in 1984. Liangjun Wang, a postdoctoral researcher in the Department of Biological Sciences, contributed to the research. The research was supported by a grant from the National Institutes of Health.
While the SMU researchers studied the E(Z) protein in Drosophila, UNC researchers succeeded in purifying a protein complex that includes a human version of the E(Z) protein. In the chromosomes of all animal and plant cells, DNA is associated with chromosomal proteins as chromatin. An important aspect of gene regulation involves modifying the manner in which individual genes are packaged in chromatin, which may permit or prevent their expression. The SMU and UNC groups demonstrated that E(Z) silences genes by making specific modifications to a particular chromatin protein and that this mechanism is the same in both humans and Drosophila.
"This is a fundamental discovery about how chromatin can repress gene expression," said Larry Ruben, chair of the Department of Biological Sciences at SMU.
Research in SMU's Department of Biological Sciences focuses on four key scientific areas: the control of gene expression, the ability of life to capture energy, the mechanisms of aging and how infectious agents affect cellular behavior.
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