Mouse homolog of Saccharomyces cerevisiae spo11 is induced in normal mu(+)B-cells by stimuli that cause germline C(H) transcription and subsequent class switch recombination.
The first step of Ig heavy chain class switch recombination (CSR) is considered to be DNA double strand break (DSB) formation in the two switch (S) regions (S(mu) and downstream S(H)), although the underlying mechanism is unknown. Recently, it has been demonstrated that at least Spo11, a homolog of the novel type II topoisomerase (topo VI) that catalyzes DSB formation, is involved in the initiation of meiotic recombination of Saccaromyces cerevisiae. In the present study, we examined whether the mouse homolog of Spo11 is induced in normal mouse mu(+)B-cells by stimuli that cause an early step of CSR, germline C(H) transcription, and subsequent CSR. Two CSR systems were used: IgA CSR induced by all-trans retinoic acid, IL-5, and LPS, and IgG1 CSR induced by IL-4 and LPS. Germline transcript and mouse Spo11 expression were analyzed by RT-PCR. In both systems, first germline transcripts were clearly detected on day 2 and then Spo11 was detected on day 3, increasing thereafter with time. The time course of changes in Spo11 expression coincided with that of CSR. Spo11 seems to be induced by CSR-inducing stimuli, regardless of the direction of CSR. These results suggested that mouse Spo11 might participate in the initiation step of CSR.
Tokuyama
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H
Department of Molecular Oncology, Cancer Research Institute, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa-ken, 920-0934, Japan.
Tokuyama
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Y
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D045643:DNA Repair Enzymes; D004250:DNA Topoisomerases, Type II / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000302:isolation & purification; D004706:Endodeoxyribonucleases; D004950:Esterases / Q000378:metabolism*; D043211:Exodeoxyribonuclease V; D005090:Exodeoxyribonucleases / Q000302:isolation & purification; D007070:Immunoglobulin A / Q000235:genetics; D017578:Immunoglobulin Class Switching; D007074:Immunoglobulin G / Q000235:genetics; D015847:Interleukin-4 / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D000076228:MRE11 Homologue Protein; D008540:Meiosis / Q000235:genetics; D051379:Mice; D051135:Rad51 Recombinase; D051721:Rad52 DNA Repair and Recombination Protein; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D014158:Transcription, Genetic; D000099257:Meiotic Recombination Protein SPO11
D045643:DNA Repair Enzymes; D004250:DNA Topoisomerases, Type II; D004268:DNA-Binding Proteins; D004706:Endodeoxyribonucleases; D004950:Esterases; D043211:Exodeoxyribonuclease V; D005090:Exodeoxyribonucleases; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D015847:Interleukin-4; D008070:Lipopolysaccharides; D000076228:MRE11 Homologue Protein; D051135:Rad51 Recombinase; D051721:Rad52 DNA Repair and Recombination Protein; D029701:Saccharomyces cerevisiae Proteins; D000099257:Meiotic Recombination Protein SPO11; C512689:Mre11a protein, mouse; C497197:RAD52 protein, S cerevisiae; C495151:RAD51 protein, S cerevisiae; C495154:Rad51 protein, mouse