Published online 4 November 2004
Nucleic Acids Research, Vol. 32 No. 19 © Oxford University Press 2004; all rights reserved
Cis-acting regulatory sequences promote high-frequency gene conversion between repeated sequences in mammalian cells
Department of Molecular Biology and Genetics, College of Biological Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1
* To whom correspondence should be addressed. Tel: +1 519 824 4120; Ext. 54788; Fax: +1 519 837 2075; Email: mdbaker{at}uoguelph.ca
Received August 6, 2004; Revised and Accepted October 19, 2004
In mammalian cells, little is known about the nature of recombination-prone regions of the genome. Previously, we reported that the immunoglobulin heavy chain (IgH) µ locus behaved as a hotspot for mitotic, intrachromosomal gene conversion (GC) between repeated µ constant (Cµ) regions in mouse hybridoma cells. To investigate whether elements within the µ gene regulatory region were required for hotspot activity, gene targeting was used to delete a 9.1 kb segment encompassing the µ gene promoter (Pµ), enhancer (Eµ) and switch region (Sµ) from the locus. In these cell lines, GC between the Cµ repeats was significantly reduced, indicating that this recombination-enhancing sequence (RES) is necessary for GC hotspot activity at the IgH locus. Importantly, the RES fragment stimulated GC when appended to the same Cµ repeats integrated at ectopic genomic sites. We also show that deletion of Eµ and flanking matrix attachment regions (MARs) from the RES abolishes GC hotspot activity at the IgH locus. However, no stimulation of ectopic GC was observed with the Eµ/MARs fragment alone. Finally, we provide evidence that no correlation exists between the level of transcription and GC promoted by the RES. We suggest a model whereby Eµ/MARS enhances mitotic GC at the endogenous IgH µ locus by effecting chromatin modifications in adjacent DNA.
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
E. Schildkraut, C. A. Miller, and J. A. Nickoloff Gene conversion and deletion frequencies during double-strand break repair in human cells are controlled by the distance between direct repeats Nucleic Acids Res., March 14, 2005; 33(5): 1574 - 1580. [Abstract] [Full Text] [PDF] |
||||
