The ArabidopsisAt1g30680 gene encodes a homologue to the phage T7 gp4 protein that has both DNA primase and DNA helicase activities

BMC Plant Biology

Research Article

John D Cupp¹  Travis Hunt¹  Joann Diray-Arce¹  Bin Liu¹  Brent L Nielsen¹ 

[1] Dept. of Microbiology & Molecular Biology, 775 WIDB, Brigham Young University, 84602, Provo, Utah, USA;

关键词: DNA primase;    DNA helicase;    bacteriophage T7 gp4;    Twinkle;    Organelle DNA replication;   

DOI  :  10.1186/1471-2229-13-36

 received in 2012-12-18, accepted in 2013-02-26,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundThe Arabidopsis thaliana genome encodes a homologue of the full-length bacteriophage T7 gp4 protein, which is also homologous to the eukaryotic Twinkle protein. While the phage protein has both DNA primase and DNA helicase activities, in animal cells Twinkle is localized to mitochondria and has only DNA helicase activity due to sequence changes in the DNA primase domain. However, Arabidopsis and other plant Twinkle homologues retain sequence homology for both functional domains of the phage protein. The Arabidopsis Twinkle homologue has been shown by others to be dual targeted to mitochondria and chloroplasts.ResultsTo determine the functional activity of the Arabidopsis protein we obtained the gene for the full-length Arabidopsis protein and expressed it in bacteria. The purified protein was shown to have both DNA primase and DNA helicase activities. Western blot and qRT-PCR analysis indicated that the Arabidopsis gene is expressed most abundantly in young leaves and shoot apex tissue, as expected if this protein plays a role in organelle DNA replication. This expression is closely correlated with the expression of organelle-localized DNA polymerase in the same tissues. Homologues from other plant species show close similarity by phylogenetic analysis.ConclusionsThe results presented here indicate that the Arabidopsis phage T7 gp4/Twinkle homologue has both DNA primase and DNA helicase activities and may provide these functions for organelle DNA replication.

【 授权许可】

Unknown   
© Diray-Arce et al.; licensee BioMed Central Ltd. 2013. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.