Gap-filling DNA synthesis by HeLa DNA polymerase. cap alpha. in an in vitro base excision DNA repair scheme

Journal Article · Sat Aug 25 04:00:00 EDT 1984 · J. Biol. Chem.; (United States)

OSTI ID:5234437

Mosbaugh, D W; Linn, S

The ability of HeLa DNA polymerase ..cap alpha.. to utilize gapped PM2 DNAs for synthesis in a model base excision DNA repair scheme was examined. Partially depurinated PM2 DNA was incised on the 5' side of apurinic sites with HeLa apurinic/apyrimidinic endonuclease II, then the baseless sugar was removed and gaps of defined mean lengths were introduced at these sites by exonucleolytic digestion with HeLa DNase V. Gaps smaller than approximately 15 nucleotides did not serve as efficient primer-templates for DNA polymerase ..cap alpha... Gaps with mean lengths of 20-63 nucleotides did support limited DNA synthesis, but such synthesis terminated after the gap was reduced to roughly 15 nucleotides. These products were not substrates for Escherichia coli DNA ligase. In contrast, HeLa DNA polymerase ..beta.. utilize as primer-templates all of the gapped DNA substrates tested though it acted more efficiently with the smaller gaps. Moreover, the ..beta..-polymerase was capable of filling these gaps to completion. In the case of the gaps that remained after partial closure by DNA polymerase ..cap alpha.., DNA polymerase ..beta.. incorporated roughly 15 nucleotides and formed a product which was a substrate for DNA ligase. These results suggest that in vivo DNA repair pathways that involve a gap-filling DNA synthesis reaction might utilize DNA polymerase ..cap alpha.. only for larger gaps.

• Research Organization: Univ. of California, Berkeley
• OSTI ID: 5234437
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 259:16; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
BIOCHEMISTRY
BIOLOGICAL PATHWAYS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CHEMISTRY
DNA POLYMERASES
DNA REPAIR
DNA REPLICATION
ENZYME ACTIVITY
ENZYMES
HELA CELLS
IN VITRO
NUCLEIC ACID REPLICATION
NUCLEOTIDYLTRANSFERASES
PHOSPHORUS-GROUP TRANSFERASES
POLYMERASES
RECOVERY
REPAIR
TRANSFERASES