Human DNA polymerase lambda possesses terminal deoxyribonucleotidyl transferase activity and can elongate RNA primers: implications for novel functions.
DNA polymerase lambda is a novel enzyme of the family X of DNA polymerases. The recent demonstration of an intrinsic 5'-deoxyribose-5'-phosphate lyase activity, a template/primer dependent polymerase activity, a distributive manner of DNA synthesis and sequence similarity to DNA polymerase beta suggested a novel beta-like enzyme. All these properties support a role of DNA polymerase lambda in base excision repair. On the other hand, the biochemical properties of the polymerisation activity of DNA polymerase lambda are still largely unknown. Here we give evidence that human DNA polymerase lambda has an intrinsic terminal deoxyribonucleotidyl transferase activity that preferentially adds pyrimidines onto 3'OH ends of DNA oligonucleotides. Furthermore, human DNA polymerase lambda efficiently elongates an RNA primer hybridized to a DNA template. These two novel properties of human DNA polymerase lambda might suggest additional roles for this enzyme in DNA replication and repair processes.
Ramadan
Kristijan
K
Institute of Veterinary Biochemistry and Molecular Biology, University of Zürich-Irchel, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
Maga
Giovanni
G
Shevelev
Igor V
IV
Villani
Giuseppe
G
Blanco
Luis
L
Hübscher
Ulrich
U
D001483:Base Sequence; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004253:DNA Nucleotidylexotransferase / Q000378:metabolism*; D019951:DNA Polymerase beta / Q000235:genetics / Q000378:metabolism*; D004260:DNA Repair / Q000502:physiology; D004261:DNA Replication / Q000502:physiology; D006801:Humans; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D019761:Phosphorus-Oxygen Lyases / Q000378:metabolism; D011743:Pyrimidines / Q000737:chemistry / Q000378:metabolism; D012313:RNA / Q000737:chemistry / Q000378:metabolism*; D013379:Substrate Specificity; D013698:Templates, Genetic
D011743:Pyrimidines; C034477:RNA primers; D012313:RNA; D004247:DNA; C423906:5'-deoxyribose phosphate lyase; C415367:DNA polymerase beta2; D004253:DNA Nucleotidylexotransferase; D019951:DNA Polymerase beta; D019761:Phosphorus-Oxygen Lyases