Nucleic Acids Research Advance Access originally published online on August 17, 2007
Nucleic Acids Research 2007 35(16):5499-5510; doi:10.1093/nar/gkm502
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Nucleic Acids Research, 2007, Vol. 35, No. 16 5499-5510
© 2007 The Author(s)
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Molecular Biology |
Hairpin structure within the 3'UTR of DNA polymerase ß mRNA acts as a post-transcriptional regulatory element and interacts with Hax-1
bieta Sarnowska1
ski1ska1
odzimierz J. Krzyosiak2
1Cancer Center Institute, Roentgena 5, 02-781 Warsaw, 2Institute of Bioorganic Chemistry, PAS, Noskowskiego 12/14, 61-704, Pozna and 3Institute of Biochemistry and Biophysics, PAS, Pawiskiego 5A, 02-106, Warsaw, Poland
*To whom correspondence should be addressed. Tel: +48 22 546 23 68; Fax: +48 22 644 02 09; Email: ewag{at}coi.waw.pl
Received January 30, 2007. Revised June 8, 2007. Accepted June 8, 2007.
Aberrant expression of DNA polymerase ß, a key enzyme involved in base excision repair, leads to genetic instability and carcinogenesis. Pol ß expression has been previously shown to be regulated at the level of transcription, but there is also evidence of post-transcriptional regulation, since rat transcripts undergo alternative polyadenylation, and the resulting 3'UTR contain at least one regulatory element. Data presented here indicate that RNA of the short 3'UTR folds to form a strong secondary structure (hairpin). Its regulatory role was established utilizing a luciferase-based reporter system. Further studies led to the identification of a protein factor, which binds to this element—the anti-apoptotic, cytoskeleton-related protein Hax-1. The results of in vitro binding analysis indicate that the formation of the RNA–protein complex is significantly impaired by disruption of the hairpin motif. We demonstrate that Hax-1 binds to Pol ß mRNA exclusively in the form of a dimer. Biochemical analysis revealed the presence of Hax-1 in mitochondria, but also in the nuclear matrix, which, along with its transcript-binding properties, suggests that Hax-1 plays a role in post-transcriptional regulation of expression of Pol ß.
The authors wish it to be known that, in their opinion, the first two authors should be regarded as joint First Authors