Journal Article

Effects of dyskeratosis congenita mutations in dyskerin, NHP2 and NOP10 on assembly of H/ACA pre-RNPs

Christian Trahan, Caroline Martel and François Dragon

in Human Molecular Genetics

Volume 19, issue 5, pages 825-836
Published in print March 2010 | ISSN: 0964-6906
Published online December 2009 | e-ISSN: 1460-2083 | DOI: http://dx.doi.org/10.1093/hmg/ddp551
Effects of dyskeratosis congenita mutations in dyskerin, NHP2 and NOP10 on assembly of H/ACA pre-RNPs

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Dyskeratosis congenita (DC) is a rare genetic syndrome that gives rise to a variety of disorders in affected individuals. Remarkably, all causative gene mutations identified to date share a link to telomere/telomerase biology. We found that the most prevalent dyskerin mutation in DC (A353V) did not affect formation of the NAF1-dyskerin-NOP10-NHP2 tetramer that normally assembles with nascent H/ACA RNAs in vivo. However, the A353V mutation slightly reduced pre-RNP assembly with the H/ACA-like domain of human telomerase RNA (hTR). In contrast, NHP2 mutations V126M and Y139H impaired association with NOP10, leading to major pre-RNP assembly defects with all H/ACA RNAs tested, including the H/ACA domain of hTR. Mutation R34W in NOP10 caused no apparent defect in protein tetramer formation, but it severely affected pre-RNP assembly with the H/ACA domain of hTR and a subset of H/ACA RNAs. Surprisingly, H/ACA sno/scaRNAs that encode miRNAs were not affected by the mutation R34W, and they were able to form pre-RNPs with NOP10-R34W. This indicates structural differences between H/ACA RNPs that encode miRNAs and those that do not. Altogether, our results suggest that, in addition to major defects in the telomere/telomerase pathways, some of the disorders occurring in DC may be caused by alteration of most H/ACA RNPs, or by only a subset of them.

Journal Article.  7186 words.  Illustrated.

Subjects: Genetics and Genomics

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