Journal of Electron Microscopy Advance Access originally published online on September 5, 2005
Journal of Electron Microscopy 2005 54(4):403-408; doi:10.1093/jmicro/dfi058
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Guanine is indispensable for immunoglobulin switch region RNA–DNA hybrid formation
1 Research Institute for Biological Sciences, Tokyo University of Science, 2669 Yamazaki, Noda, Chiba 278-0022, Japan and 2 Genome and Drug Research Centre, Tokyo University of Science, 2669 Yamazaki, Noda, Chiba 278-0022, Japan
* To whom correspondence should be addressed. E-mail: mizuta{at}rs.noda.tus.ac.jp
It is suggested that the formation of the switch (S) region RNA–DNA hybrid and the subsequent generation of higher-order chromatin structures including R-loop initiate a class switch recombination of the immunoglobulin gene. The primary factor of this recombination is the S-region derived noncoding RNA. However, the biochemical character of this guanine-rich (G-rich) transcript is poorly understood. The present study was performed to analyze the structure of this G-rich RNA using atomic force microscope (AFM). The in vitro transcribed S-region RNA was spread on a mica plate, air-dried and observed by non-contact mode AFM in air. The G-rich transcripts tend to aggregate on the template DNA and to generate a higher-order RNA–DNA complex. However, the transcripts that incorporated guanine analogues as substitutes for guanine neither aggregated nor generated higher-order structures. Incorporation of guanine analogues in transcribed RNA partially disrupts hydrogen bonds related to guanine, such as Watson–Crick GC-base pair and Hoogsteen bond GG-base pair. Thus, aggregation of S-region RNA and generation of the higher-order RNA–DNA complex are attributed to hydrogen bonds of guanine.
Keywords immunoglobulin gene, class switch recombination, atomic force microscope, Hoogsteen bond, RNA–DNA hybrid
Received 17 February 2005, accepted 1 August 2005
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  F. Li, L. Sonbuchner, S. A. Kyes, C. Epp, and K. W. Deitsch Nuclear Non-coding RNAs Are Transcribed from the Centromeres of Plasmodium falciparum and Are Associated with Centromeric Chromatin J. Biol. Chem., February 29, 2008; 283(9): 5692 - 5698. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 X. Li and J. L. Manley Cotranscriptional processes and their influence on genome stability Genes & Dev., July 15, 2006; 20(14): 1838 - 1847. [Abstract] [Full Text] [PDF]
|
|