Genetic Evidence for Single-Strand Lesions Initiating Nbs1-Dependent Homologous Recombination in Diversification of Ig V in Chicken B Lymphocytes
2009

Single-Strand Gaps Initiate Ig Gene Conversion in Chicken B Lymphocytes

publication 10 minutes Evidence: moderate

Author Information

Author(s): Nakahara Makoto, Sonoda Eiichiro, Nojima Kuniharu, Sale Julian E., Takenaka Katsuya, Kikuchi Koji, Taniguchi Yoshihito, Nakamura Kyoko, Sumitomo Yoshiki, Bree Ronan T., Lowndes Noel F., Takeda Shunichi

Primary Institution: CREST Research Project, Japan Science and Technology Agency, Saitama, Japan

Hypothesis

Can single-strand lesions initiate homologous recombination in genomic DNA?

Conclusion

The study suggests that Ig gene conversion may be initiated by single-strand gaps rather than by double-strand breaks.

Supporting Evidence

  • The MRN complex is involved in the initiation of homologous recombination.
  • Single-strand gaps can be processed to trigger Ig gene conversion.
  • Overproduction of SbcB can restore Ig gene conversion in Nbs1-deficient cells.
  • Defective Nbs1 function reduces the rate of Ig gene conversion.
  • AID overexpression can normalize impaired Ig gene conversion in Nbs1-deficient cells.

Takeaway

This research shows that when DNA in chicken B cells gets damaged, it can create small gaps that help in changing the genes that make antibodies, instead of needing bigger breaks in the DNA.

Methodology

The study involved creating mutant DT40 cells and analyzing their ability to undergo Ig gene conversion and homologous recombination.

Limitations

The study primarily focuses on a specific cell line and may not fully represent other systems.

Digital Object Identifier (DOI)

10.1371/journal.pgen.1000356

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