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Journal of Biotechnology & Biomaterials | ISSN: 2155-952X | Volume: 8
&
24
th
Biotechnology Congress: Research & Innovations
CRISPR Cas9 Technology and Genetic Engineering
Annual Congress on
October 24-25, 2018 | Boston, USA
DNAbreak repair and modification guided by transcript RNA
D
oes genetic information flow from RNA to DNA in a more general fashion than anticipated? Is the central dogma of
molecular biology often reversed to let RNA repair DNA damage or even recode genes on chromosomes? We recently
discovered that RNA serves as a template to repair DNA double-strand breaks (DSBs), either indirectly, in the form of
complementary DNA (cDNA), or directly, in the form of transcript-RNA in budding yeast. We found that transfer of genetic
information from RNA to DNA occurs with an endogenous generic transcript in cis, and is thus a more common mechanism
than previously anticipated. With the advent of CRISPR RNA-guided DNA endonuclease enzymes, there is marked interest in
understanding the pathways to facilitate accurate genome engineering events. While ribonucleases (RNases) H1 and H2 block
DSB repair by RNA, the recombination protein Rad52 is a key factor for this repair mechanism. DSB repair by RNA requires
Rad52 but not the recombination protein Rad51, RecA homolog, or Rad59, which has homology with the yRad52 N-terminal
domain (NTD). Upon overexpression of yRad52,yeast or hRad52 NTD, we observed a significant increase in the frequency
of DSB repair by RNA. A 68-fold increase was obtained when hRad52 NTD was expressed in cells defective for RNase H
function that was lacking the yeast RAD52 gene, indicating that hRad52 could catalyze DSB repair by RNA also in human cells.
Moreover, in the absence of SAE2 or EXO1 genes, which are important for DNA end resection, the frequency of DSB repair
by RNA was either increased or not changed, respectively. These results support an RNA-dependent mechanism of DSB repair
mediated by Rad52 that catalyzes a reaction in which RNA invades a broken double-stranded DNA in conditions of limited end
resection. Our results suggest that transcript RNA, like non-coding RNA, may have a significant role in genome stability and
genome modification, much more prominent than previously anticipated.
Biography
Francesca Storici received her PhD in Molecular Genetics from the International School of Advanced Studiein Trieste, Italy (1998). She was a postdoctoral fellow at
the National Institute of Environmental and Health Sciences (NIEHS, NIH), NC till 2007, and then research assistant professor at the Gene Therapy Center of the
University of North Carolina at Chapel Hill, NC. She joined the Georgia Institute of Technology as an assistant professor in 2007, and became Distinguished Cancer
Scientist of the Georgia.Research Alliance. In 2013, she was promoted to Associate Professor with tenure. In 2016, she became Howard Hughes Medical Institute
Faculty Scholar. Just recently, she was promoted to Full Professor. Her research is DNA damage, repair and gene editing.
storici@gatech.eduFrancesca Storici
Georgia Institute of Technology, Atlanta, USA
Francesca Storici, J Biotechnol Biomater 2018, Volume 8
DOI: 10.4172/2155-952X-C4-096