活化B细胞染色体上免疫球蛋白类别转换区的R环。

R-loops at immunoglobulin class switch regions in the chromosomes of stimulated B cells.

作者信息

Yu Kefei, Chedin Frederic, Hsieh Chih-Lin, Wilson Thomas E, Lieber Michael R

机构信息

USC Norris Comprehensive Cancer Center, Room 5428, University of Southern California Keck School of Medicine, 1441 Eastlake Avenue, MC 9176, Los Angeles, CA 90033, USA.

出版信息

Nat Immunol. 2003 May;4(5):442-51. doi: 10.1038/ni919.

DOI:10.1038/ni919

PMID:12679812

Abstract

The mechanism responsible for immunoglobulin class switch recombination is unknown. Previous work has shown that class switch sequences have the unusual property of forming RNA-DNA hybrids when transcribed in vitro. Here we show that the RNA-DNA hybrid structure that forms in vitro is an R-loop with a displaced guanine (G)-rich strand that is single-stranded. This R-loop structure exists in vivo in B cells that have been stimulated to transcribe the gamma3 or the gamma2b switch region. The length of the R-loops can exceed 1 kilobase. We propose that this distinctive DNA structure is important in the class switch recombination mechanism

摘要

负责免疫球蛋白类别转换重组的机制尚不清楚。先前的研究表明，类别转换序列在体外转录时具有形成RNA-DNA杂交体的特殊性质。在此我们表明，体外形成的RNA-DNA杂交结构是一种R环，其富含鸟嘌呤（G）的链被置换且为单链。这种R环结构存在于已被刺激转录γ3或γ2b转换区的B细胞体内。R环的长度可超过1千碱基。我们提出，这种独特的DNA结构在类别转换重组机制中很重要。