Extracts of proliferating and non-proliferating human cells display different base excision pathways and repair fidelity

TY - JOUR

T1 - Extracts of proliferating and non-proliferating human cells display different base excision pathways and repair fidelity

AU - Akbari, Mansour

AU - Pena Diaz, Javier

AU - Andersen, Sonja

AU - Liabakk, Nina-Beate

AU - Otterlei, Marit

AU - Krokan, Hans Einar

PY - 2009/7/4

Y1 - 2009/7/4

N2 - Base excision repair (BER) of damaged or inappropriate bases in DNA has been reported to take place by single nucleotide insertion or through incorporation of several nucleotides, termed short-patch and long-patch repair, respectively. We found that extracts from proliferating and non-proliferating cells both had capacity for single- and two-nucleotide insertion BER activity. However, patch size longer than two nucleotides was only detected in extracts from proliferating cells. Relative to extracts from proliferating cells, extracts from non-proliferating cells had approximately two-fold higher concentration of POLbeta, which contributed to most of two-nucleotide insertion BER. In contrast, two-nucleotide insertion in extracts from proliferating cells was not dependent on POLbeta. BER fidelity was two- to three-fold lower in extracts from the non-proliferating compared with extracts of proliferating cells. Furthermore, although one-nucleotide deletion was the predominant type of repair error in both extracts, the pattern of repair errors was somewhat different. These results establish two-nucleotide patch BER as a distinct POLbeta-dependent mechanism in non-proliferating cells and demonstrate that BER fidelity is lower in extracts from non-proliferating as compared with proliferating cells.

AB - Base excision repair (BER) of damaged or inappropriate bases in DNA has been reported to take place by single nucleotide insertion or through incorporation of several nucleotides, termed short-patch and long-patch repair, respectively. We found that extracts from proliferating and non-proliferating cells both had capacity for single- and two-nucleotide insertion BER activity. However, patch size longer than two nucleotides was only detected in extracts from proliferating cells. Relative to extracts from proliferating cells, extracts from non-proliferating cells had approximately two-fold higher concentration of POLbeta, which contributed to most of two-nucleotide insertion BER. In contrast, two-nucleotide insertion in extracts from proliferating cells was not dependent on POLbeta. BER fidelity was two- to three-fold lower in extracts from the non-proliferating compared with extracts of proliferating cells. Furthermore, although one-nucleotide deletion was the predominant type of repair error in both extracts, the pattern of repair errors was somewhat different. These results establish two-nucleotide patch BER as a distinct POLbeta-dependent mechanism in non-proliferating cells and demonstrate that BER fidelity is lower in extracts from non-proliferating as compared with proliferating cells.

KW - Base Sequence

KW - Binding Sites

KW - Blotting, Western

KW - Cell Extracts

KW - Cell Line

KW - Cell Proliferation

KW - Cells, Cultured

KW - DNA Polymerase beta

KW - DNA Repair

KW - Humans

KW - Keratinocytes

KW - Lymphocytes

KW - Mutation

KW - Oligonucleotides

KW - Signal Transduction

KW - Substrate Specificity

U2 - 10.1016/j.dnarep.2009.04.002

DO - 10.1016/j.dnarep.2009.04.002

M3 - Journal article

C2 - 19442590

SN - 1568-7864

VL - 8

SP - 834

EP - 843

JO - DNA Repair

JF - DNA Repair

IS - 7

ER -