Isolation of mammalian pol beta type DNA polymerase in shoot tips of germinated seedlings of IR-8 rice (Oryza sativa L.).
A single polypeptide of approx. 67 kDa mol.wt. with DNA polymerase activity has been chromatographically purified from shoot tips of 72 hr. grown germinated seedlings of rice (Oryza sativa.L.cv IR-8). An approx. 4800 fold enrichment of specific activity was measured by the incorporation of 3H-dTMP into trichloroacetic acid insoluble fraction, using activated calf thymus DNA as template-primer. The enzyme uses different types of DNA but not RNA as a template. The enzyme requires Mg+2, high KCl, and is highly sensitive to dideoxyribonucleoside triphosphate but is unaffected by aphidicolin, suggesting a plant counterpart of mammalian DNA polymerase beta. Replication of M13mp18 single stranded DNA by extension of 5'32P-labeled 17-mer primer(-40) showed distributive type of DNA synthesis by the rice DNA polymerase beta, which is a characteristic feature of mammalian DNA polymerase beta.
Sanathkumar
M
M
Department of Botany, Bose Institute, Calcutta, India.
Ghosh
B
B
SenGupta
D N
DN
D004256:DNA Polymerase I / Q000302:isolation & purification*; D018525:Germination / Q000502:physiology; D012275:Oryza / Q000201:enzymology*; D018520:Plant Shoots / Q000201:enzymology*; D012639:Seeds / Q000201:enzymology
D004256:DNA Polymerase I