Studies in mice have shown that loss of H2AX, a gene that produces a protein called a histone that is part of the chromosomal structure, can tip the delicate balance of proteins that are curators of the human genome. When H2AX ceases to function properly, lymphomas and solid tumors can arise because errors in the genetic code are not always repaired correctly, according to the new research.
The finding may have important implications for understanding the origin of human cancers because a large number of human tumors are known to contain alterations in the region of chromosome 11 where the H2AX gene is located.
The research was reported in an article published in the August 8, 2003, issue of the journal Cell by Howard Hughes Medical Institute investigator Frederick Alt and colleagues at Children's Hospital in Boston and Harvard Medical School. Other co-authors are from the Tufts University School of Veterinary Medicine and Brigham and Women's Hospital.
According to Alt, previous studies by other researchers had shown that H2AX was activated when DNA breaks occur. DNA repair proteins fix genetic damage, but they are also called to action during the normal gene rearrangement that occurs in immune cells when they are readying to battle viruses and other threats.
To explore the implications of knocking out the H2AX gene, lead author Craig Bassing created a line of mice lacking both copies of the H2AX gene. "Both Craig in our lab and Andre Nussenzweig at the National Cancer Institute produced knockout strains that showed an increased level of genomic instability," said Alt. Nussenzweig and his co
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Contact: Jim Keeley
keeleyj@hhmi.org
301-215-8858
Howard Hughes Medical Institute
7-Aug-2003