TY - JOUR
T1 - APOBEC3G enhances lymphoma cell radioresistance by promoting cytidine deaminase-dependent DNA repair
AU - Nowarski, Roni
AU - Wilner, Ofer I.
AU - Cheshin, Ori
AU - Shahar, Or D.
AU - Kenig, Edan
AU - Baraz, Leah
AU - Britan-Rosich, Elena
AU - Nagler, Arnon
AU - Harris, Reuben S.
AU - Goldberg, Michal
AU - Willner, Itamar
AU - Kotler, Moshe
PY - 2012/7/12
Y1 - 2012/7/12
N2 - APOBEC3 proteins catalyze deamination of cytidines in single-stranded DNA (ssDNA), providing innate protection against retroviral replication by inducing deleteriousdC 〉 dUhypermutation of replication intermediates. APOBEC3G expression is induced in mitogen-activated lymphocytes; however, no physiologic role related to lymphoid cell proliferation has yet to be determined. Moreover, whether APOBEC3G cytidine deaminase activity transcends to processing cellular genomic DNA is unknown. Here we show that lymphoma cells expressing high APOBEC3G levels display efficient repair of genomic DNA doublestrand breaks (DSBs) induced by ionizing radiation and enhanced survival of irradiated cells. APOBEC3G transiently accumulated in the nucleus in response to ionizing radiation and was recruited to DSB repair foci. Consistent with a direct role in DSB repair, inhibition of APOBEC3G expression or deaminase activity resulted in deficient DSB repair, whereas reconstitution of APOBEC3G expression in leukemia cells enhanced DSB repair. APOBEC3G activity involved processing of DNA flanking a DSB in an integrated reporter cassette. Atomic force microscopy indicated thatAPOBEC3G multimers associate with ssDNA termini, triggering multimer disassembly to multiple catalytic units. These results identify APOBEC3G as a prosurvival factor in lymphoma cells, marking APOBEC3G as a potential target for sensitizing lymphoma to radiation therapy.
AB - APOBEC3 proteins catalyze deamination of cytidines in single-stranded DNA (ssDNA), providing innate protection against retroviral replication by inducing deleteriousdC 〉 dUhypermutation of replication intermediates. APOBEC3G expression is induced in mitogen-activated lymphocytes; however, no physiologic role related to lymphoid cell proliferation has yet to be determined. Moreover, whether APOBEC3G cytidine deaminase activity transcends to processing cellular genomic DNA is unknown. Here we show that lymphoma cells expressing high APOBEC3G levels display efficient repair of genomic DNA doublestrand breaks (DSBs) induced by ionizing radiation and enhanced survival of irradiated cells. APOBEC3G transiently accumulated in the nucleus in response to ionizing radiation and was recruited to DSB repair foci. Consistent with a direct role in DSB repair, inhibition of APOBEC3G expression or deaminase activity resulted in deficient DSB repair, whereas reconstitution of APOBEC3G expression in leukemia cells enhanced DSB repair. APOBEC3G activity involved processing of DNA flanking a DSB in an integrated reporter cassette. Atomic force microscopy indicated thatAPOBEC3G multimers associate with ssDNA termini, triggering multimer disassembly to multiple catalytic units. These results identify APOBEC3G as a prosurvival factor in lymphoma cells, marking APOBEC3G as a potential target for sensitizing lymphoma to radiation therapy.
UR - http://www.scopus.com/inward/record.url?scp=84864028244&partnerID=8YFLogxK
U2 - 10.1182/blood-2012-01-402123
DO - 10.1182/blood-2012-01-402123
M3 - Article
C2 - 22645179
AN - SCOPUS:84864028244
SN - 0006-4971
VL - 120
SP - 366
EP - 375
JO - Blood
JF - Blood
IS - 2
ER -
