Deciphering the Domain-Specific Functions of Polymerase Theta During Interstrand Crosslink Repair in Drosophila Melanogaster.
Armstrong, Robin L.
2014
- Abstract: DNA polymerase θ (Pol θ) is upregulated in many human cancers which is associated with a poor prognosis for these cancer patients. The D. melanogaster homologue of Pol θ is encoded by mus308 and contains two domains, an N-terminal helicase-like domain and a C-terminal polymerase domain, connected by a central, non-conserved linker region. Unlike human Pol θ mutants, which are extremely ... read moreradiosensitive, D. melanogaster mus308 mutants demonstrate extreme sensitivity to interstrand crosslinking (ICL) agents, such as nitrogen mustard (HN2), but are not radiosensitive. In order to investigate the domain-specific functions of Pol θ during ICL repair, we generated a host of Pol θ domain-specific mutants. Our HN2 sensitivity studies with ATPase-dead and polymerase-dead transgenic flies have demonstrated that the helicase-like domain of Pol θ is essential for the repair of HN2 induced ICLs while polymerase-dead flies were only moderately sensitive to ICL agents. Flies which express truncated Pol θ protein expressing part of the linker region and either only the N-terminus or C-terminus are equally extremely sensitive to HN2. These suggests that the C-terminus of Pol θ could have some function in recruitment of other proteins to ICLs outside of its catalytic function. It has been shown that the sensitivity to HN2 is partially rescued in flies which express the N- and C-termini of the protein in trans, suggesting that there is not an absolute requirement that the two catalytic domains be part of the same polypeptide. Our data support a model in which the helicase-like domain of Pol θ functions upstream of the polymerase domain and is crucial for repair of HN2 induced ICLs. Furthermore, we propose that the presence, but not the catalytic function, of the polymerase domain is also required for proper repair of ICLs.read less
- ID:
- fj236d57t
- Component ID:
- tufts:sd.0000076
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- TARC Citation Guide EndNote
