The involvement of alternative DNA structures in chromosome translocations and other rearrangements has gained attention in recent years. One type of alternative structure, a cruciform, has been demonstrated to form at DNA sequences that comprise a palindrome in vitro. While strong evidence causally implicates long palindromic DNA sequences with heritable reciprocal translocations in humans, whether palindromes contribute to translocation in cells other than germ cells has not been demonstrated. The possibility is particularly relevant in the case of T and B lymphoid cells where there are extra demands placed upon accurate DNA metabolism during differentiation, and where, although translocation is a marked feature in tumors of the lymphoid system, the underlying errors have been only partially defined. The purpose of the present study is to test the notion that (long) DNA palindromes can instigate translocation in pro/pre B cells. The relationship between palindromy and translocation in mouse pro B cell lines (transformed by Abelson murine leukemia virus), and in a human pre-B line, Nalm6, will be investigated. A recently developed method for characterizing translocation at a genome-wide level will be employed. These studies may establish a new category of endogenously generated DNA damage with significance in tumorigenesis and other pathologies in the lymphoid system and beyond.

Public Health Relevance

Enzymes that work on DNA in order to replicate, transcribe, recombine or modify the molecule all recognize specific structures. Certain DNA sequences have a tendency to assume locally abnormal conformations, and these pose the risk of being improperly manipulated by DNA enzymes. The present proposal is aimed at analyzing a particular DNA sequence motif (an inverted repeat sequence with no central spacer) that has a tendency to form branched 'cruciform'structures, for its ability to instigate chromosomal translocations in cells.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21AI097825-01
Application #
8229461
Study Section
Cellular and Molecular Immunology - A Study Section (CMIA)
Program Officer
Nasseri, M Faraz
Project Start
2012-08-06
Project End
2014-07-31
Budget Start
2012-08-06
Budget End
2013-07-31
Support Year
1
Fiscal Year
2012
Total Cost
$240,000
Indirect Cost
$90,000
Name
University of Pennsylvania
Department
Pathology
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Gigi, Vered; Lewis, Susanna; Shestova, Olga et al. (2014) RAG2 mutants alter DSB repair pathway choice in vivo and illuminate the nature of 'alternative NHEJ'. Nucleic Acids Res 42:6352-64