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Arabidopsis thaliana AtPOLK encodes a DinB-like DNA polymerase that extends mispaired primer termini and is highly expressed in a variety of tissues.
- Source :
-
The Plant journal : for cell and molecular biology [Plant J] 2004 Jul; Vol. 39 (1), pp. 84-97. - Publication Year :
- 2004
-
Abstract
- Cell survival after DNA damage depends on specialized DNA polymerases able to perform DNA synthesis on imperfect templates. Most of these enzymes belong to the recently discovered Y-family of DNA polymerases, none of which has been previously described in plants. We report here the isolation, functional characterization and expression analysis of a plant representative of the Y-family. This polymerase, which we have termed AtPolkappa, is a homolog of Escherichia coli pol IV and human pol kappa, and thus belongs to the DinB subfamily. We purified AtPolkappa and found a template-directed DNA polymerase, endowed with limited processivity that is able to extend primer-terminal mispairs. The activity and processivity of AtPolkappa are enhanced markedly upon deletion of 193 amino acids (aa) from its carboxy (C)-terminal domain. Loss of this region also affects the nucleotide selectivity of the enzyme, leading to the incorporation of both dCTP and dTTP opposite A in the template. We detected three cDNA forms, which result from the alternative splicing of AtPOLK mRNA and have distinct patterns of expression in different plant organs. Histochemical localization of beta-glucuronidase (GUS) activity in transgenic plants revealed that the AtPOLK promoter is active in endoreduplicating cells, suggesting a possible role during consecutive DNA replication cycles in the absence of mitosis.
- Subjects :
- Alternative Splicing
Amino Acid Sequence
Arabidopsis Proteins chemistry
Arabidopsis Proteins metabolism
Gene Expression
Gene Library
Molecular Sequence Data
Phylogeny
Plants, Genetically Modified
Recombinant Fusion Proteins genetics
Recombinant Fusion Proteins metabolism
Sequence Homology, Amino Acid
Arabidopsis genetics
Arabidopsis Proteins genetics
DNA-Directed DNA Polymerase genetics
Subjects
Details
- Language :
- English
- ISSN :
- 0960-7412
- Volume :
- 39
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- The Plant journal : for cell and molecular biology
- Publication Type :
- Academic Journal
- Accession number :
- 15200644
- Full Text :
- https://doi.org/10.1111/j.1365-313X.2004.02112.x