American Chemical Society
Central Ohio Valley Section
Dr. Marc M. Greenberg
Johns Hopkins University
“Histone Catalyzed Strand Scission at Damaged DNA in Nucleosomes”
Nuclear DNA is compacted in cells by wrapping around an octameric core of highly positively charged histone proteins to form nucleosomes. The individual nucleosomeunits assemble to form chromatin. The histone proteins contain lysine rich tails thatprotrude through the octameric core of the nucleosomes. Post-translational modificationof the histone proteins within nucleosomes plays a large role in gene regulation. Thenucleosome also shields damaged DNA from repair enzymes. Due to the instability ofsome DNA lesions, such as abasic sites, decreased repair efficiency in nucleosomes
poses other challenges such as increased amounts of strand scission. By takingadvantage of methods that enable one to in effect synthesize nucleosomes containingDNA lesions at defined sites, we have shown that the histone proteins catalyze DNAstrand scission at damaged DNA. Mechanistic studies indicate that the lysine richhistone tails that are often post-translationally modified accelerate cleavage by as muchas almost 500-fold and that the histone proteins act like lyase enzymes on the DNA
lesions. In some instances, the histone proteins themselves are modified as a result ofthe strand scission. The details of this chemistry and possible implications will bediscussed.
Marc Greenberg received his B.S. in Chemistry from New York University and B.E. inChemical Engineering from The Cooper Union School of Engineering in 1982. Hecarried out undergraduate research with Professor David Schuster at New YorkUniversity and Dr. Stanley Seltzer at Brookhaven National Laboratory (summer 1981).After receiving his Ph.D. from Yale University in 1988 under the guidance of ProfessorJerome A. Berson, he carried out postdoctoral research as an American Cancer Societyfellow with Professor Peter B. Dervan at the California Institute of Technology. He beganhis independent career in 1990 at Colorado State University and moved to JohnsHopkins University in 2002 where he is a Professor of Chemistry. He was foundingDirector of the Chemistry-Biology Interface graduate program at Johns HopkinsUniversity from 2005-2013. He was an Alfred P. Sloan Foundation fellow and is a fellowof the AAAS. His research group's interests encompass fundamental and applied studieson nucleic acid chemistry and they have published more than 175 refereed manuscriptsin these areas.
We had a quorum at our meeting on November 4 and we voted to adopt the proposed new bylaws. The new bylaws will not go into effect until we have completed certifying the outcome of the vote. We fully expect the new bylaws to be in effect by the end of the year.
Visit the Section's Facebook Page
Change in the way meeting notices will be sent out.
The Section spends a substantial amount of money each year for postage on meeting notices. At the November 4 meeting we discussed the option of switching to emailed notices. Those present at the meeting were strongly in favor of making the switch. This notice will be sent out by both US Mail and email. We will use both methods for this meeting and the next two after this. After that, we will only send US Mail notices to those members for whom we do not have an email address and for those who specifically request that they be sent a hardcopy notice. Requests to opt in to the hard copy notices should be sent to Dr. Gary D. Anderson, Department of Chemistry, Marshall University, Huntington, WV 25755 ore by email to email@example.com.