Stage-specific binding profiles of cohesin in resting and activated B lymphocytes suggest a role for cohesin in immunoglobulin class switching and maturation.
The immunoglobulin heavy chain locus (Igh) features higher-order chromosomal interactions to facilitate stage-specific assembly of the Ig molecule. Cohesin, a ring-like protein complex required for sister chromatid cohesion, shapes chromosome architecture and chromatin interactions important for transcriptional regulation and often acts together with CTCF. Cohesin is likely involved in B cell activation and Ig class switch recombination. Hence, binding profiles of cohesin in resting mature murine splenic B lymphocytes and at two stages after cell activation were elucidated by chromatin immunoprecipitation and deep sequencing. Comparative genomic analysis revealed cohesin extensively changes its binding to transcriptional control elements after 48 h of stimulation with LPS/IL-4. Cohesin was clearly underrepresented at switch regions regardless of their activation status, suggesting that switch regions need to be cohesin-poor. Specific binding changes of cohesin at B-cell specific gene loci Pax5 and Blimp-1 indicate new cohesin-dependent regulatory pathways. Together with conserved cohesin/CTCF sites at the Igh 3'RR, a prominent cohesin/CTCF binding site was revealed near the 3' end of Cα where PolII localizes to 3' enhancers. Our study shows that cohesin likely regulates B cell activation and maturation, including Ig class switching.
Institute of Physiological Chemistry, Faculty of Medicine Carl Gustav Carus, Dresden University of Technology, Dresden, Germany.
Gamze
G
Günal-Sadık
Department of Medical Systems Biology, University Hospital and Medical Faculty Carl Gustav Carus, Dresden University of Technology, Dresden, Germany.
Maciej
M
Paszkowski-Rogacz
Cellular Networks and Systems Biology, Biotechnology Center, Dresden University of Technology, Dresden, Germany.
Kalaimathy
K
Singaravelu
Cellular Networks and Systems Biology, Biotechnology Center, Dresden University of Technology, Dresden, Germany; CECAD, Universität zu Köln, Köln, Germany.
Andreas
A
Beyer
Department of Medical Systems Biology, University Hospital and Medical Faculty Carl Gustav Carus, Dresden University of Technology, Dresden, Germany.
Frank
F
Buchholz
Institute of Physiological Chemistry, Faculty of Medicine Carl Gustav Carus, Dresden University of Technology, Dresden, Germany.
Rolf
R
Jessberger
D000818:Animals; D001402:B-Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D002843:Chromatin / Q000187:drug effects / Q000235:genetics*; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D005786:Gene Expression Regulation; D017578:Immunoglobulin Class Switching / Q000187:drug effects; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D015847:Interleukin-4 / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D012045:Regulatory Sequences, Nucleic Acid; D013154:Spleen / Q000166:cytology; D000097722:Cohesins
D018797:Cell Cycle Proteins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D007143:Immunoglobulin Heavy Chains; D015847:Interleukin-4; D008070:Lipopolysaccharides; D000097722:Cohesins