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"DNA polymerase mu (Pol mu), homologous to TdT, could act as a DNA mutator in eukaryotic cells." |
Dominguez O, Ruiz JF, Lain de Lera T, Garcia-Diaz M, Gonzalez MA, Kirchhoff T, Martinez-A C, Bernad A, Blanco L |
Published April 3, 2000 in EMBO J volume 19 .
Pubmed ID: 10747040
Abstract:
| A novel DNA polymerase has been identified in human cells. Human DNA polymerase mu (Pol mu), consisting of 494 amino acids, has 41% identity to terminal deoxynucleotidyltransferase (TdT). Human Pol mu, overproduced in Escherichia coli in a soluble form and purified to homogeneity, displays intrinsic terminal deoxynucleotidyltransferase activity and a strong preference for activating Mn(2+) ions. Interestingly, unlike TdT, the catalytic efficiency of polymerization carried out by Pol mu was enhanced by the presence of a template strand. Using activating Mg(2+) ions, template-enhanced polymerization was also template-directed, leading to the preferred insertion of complementary nucleotides, although with low discrimination values. In the presence of Mn(2+) ions, template-enhanced polymerization produced a random insertion of nucleotides. Northern-blotting and in situ analysis showed a preferential expression of Pol mu mRNA in peripheral lymphoid tissues. Moreover, a large proportion of the human expressed sequence tags corresponding to Pol mu, present in the databases, derived from germinal center B cells. Therefore, Pol mu is a good candidate to be the mutator polymerase responsible for somatic hyper- mutation of immunoglobulin genes. |
This publication refers to following REPAIRtoire entries:
| Proteins |
Last modification of this entry: Oct. 6, 2010
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