TY - JOUR
T1 - A source of the single-stranded DNA substrate for activation-induced deaminase during somatic hypermutation
AU - Wang, Xiaohua
AU - Fan, Manxia
AU - Kalis, Susan
AU - Wei, Lirong
AU - Scharff, Matthew D.
N1 - Funding Information:
We thank Drs Barbara Birshtein, Hilda Ye, Jonathan Warner and Richard Chahwan for their critical comments on the project. We thank the core facilities at Albert Einstein College for their technical support on Flow Cytometry and shRNA viral particle preparation. Funding for this work was provided by National Institutes of Health grants R01 CA072649, R01 CA102705 and an NCI/CFAR Pilot Project from P30CA013330 to M.D.S.
PY - 2014/6/13
Y1 - 2014/6/13
N2 - During somatic hypermutation (SHM), activation-induced deaminase (AID) mutates deoxycytidine on single-stranded DNA (ssDNA) generated by the transcription machinery, but the detailed mechanism remains unclear. Here we report a higher abundance of RNA polymerase II (Pol II) at the immunoglobulin heavy-chain variable (Igh-V) region compared with the constant region and partially transcribed Igh RNAs, suggesting a slower Pol II progression at Igh-V that could result in some early/premature transcription termination after prolonged pausing/stalling of Pol II. Knocking down RNA-exosome complexes, which could decrease premature transcription termination, leads to decreased SHM. Knocking down Spt5, which can augment premature transcription termination, leads to increase in both, SHM and the abundance of ssDNA substrates. Collectively, our data support the model that, following the reduction of Pol II progression (pausing or stalling) at the Igh-V, additional steps such as premature transcription termination are involved in providing ssDNA substrates for AID during SHM.
AB - During somatic hypermutation (SHM), activation-induced deaminase (AID) mutates deoxycytidine on single-stranded DNA (ssDNA) generated by the transcription machinery, but the detailed mechanism remains unclear. Here we report a higher abundance of RNA polymerase II (Pol II) at the immunoglobulin heavy-chain variable (Igh-V) region compared with the constant region and partially transcribed Igh RNAs, suggesting a slower Pol II progression at Igh-V that could result in some early/premature transcription termination after prolonged pausing/stalling of Pol II. Knocking down RNA-exosome complexes, which could decrease premature transcription termination, leads to decreased SHM. Knocking down Spt5, which can augment premature transcription termination, leads to increase in both, SHM and the abundance of ssDNA substrates. Collectively, our data support the model that, following the reduction of Pol II progression (pausing or stalling) at the Igh-V, additional steps such as premature transcription termination are involved in providing ssDNA substrates for AID during SHM.
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U2 - 10.1038/ncomms5137
DO - 10.1038/ncomms5137
M3 - Article
C2 - 24923561
AN - SCOPUS:84902493677
SN - 2041-1723
VL - 5
JO - Nature communications
JF - Nature communications
M1 - 4137
ER -