Related Experiment Videos
Transcription-dependent R-loop formation at mammalian class switch sequences
1Department of Pathology, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1441 Eastlake Avenue, Los Angeles, CA 90089-9176, USA.
The EMBO Journal
|March 4, 2000
Summary
Immunoglobulin class switching involves RNA-DNA hybrids at switch sequences. These structures form R-loops, with a G-rich RNA strand binding the C-rich DNA, facilitating recombination.
Area of Science:
- Immunology
- Molecular Biology
- Genetics
Background:
- Immunoglobulin class switching is a key adaptive immune process.
- This process relies on recombination at specific switch (S) regions.
- Transcription through S regions is linked to recombination targeting.
Purpose of the Study:
- To define the in vitro structure of RNA-DNA hybrids at mouse switch sequences.
- To elucidate the role of these structures in immunoglobulin class switching.
Main Methods:
- In vitro analysis of switch sequences (Smicro, Sgamma3, Sgamma2b).
- DNA/RNA hybrid structure determination using probe sensitivity assays.
Main Results:
- Identified R-loop formation at mouse switch sequences.
- Demonstrated G-rich RNA strand forms a heteroduplex with the C-rich DNA strand.
- Showed the G-rich DNA strand is primarily single-stranded.
Conclusions:
- The R-loop structure is precisely organized at switch sequences.
- This organized R-loop is proposed to be essential for recruiting the class switch recombination machinery.