Insights into the evolution of mammalian telomerase: Platypus TERT shares similarities with genes of birds and other reptiles and localizes on sex chromosomes

BMC Genomics

Research Article

Radmila Hrdličková¹  Jiří Nehyba¹  Henry R Bose¹  Shu Ly Lim²  Frank Grützner² 

[1] Section of Molecular Genetics and Microbiology, School of Biological Science, and Institute for Cellular and Molecular Biology, University of Texas at Austin, 78712-1095, Austin, TX, USA;The Robinson Institute, School of Molecular and Biomedical Science, The University of Adelaide, 5005, Adelaide, SA, Australia;

关键词: Platypus;    TERT;    Telomerase;    Alternative splicing;    Telomeres;    Sex chromosomes;   

DOI  :  10.1186/1471-2164-13-216

 received in 2011-10-26, accepted in 2012-05-04,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundThe TERT gene encodes the catalytic subunit of the telomerase complex and is responsible for maintaining telomere length. Vertebrate telomerase has been studied in eutherian mammals, fish, and the chicken, but less attention has been paid to other vertebrates. The platypus occupies an important evolutionary position, providing unique insight into the evolution of mammalian genes. We report the cloning of a platypus TERT (OanTERT) ortholog, and provide a comparison with genes of other vertebrates.ResultsThe OanTERT encodes a protein with a high sequence similarity to marsupial TERT and avian TERT. Like the TERT of sauropsids and marsupials, as well as that of sharks and echinoderms, OanTERT contains extended variable linkers in the N-terminal region suggesting that they were present already in basal vertebrates and lost independently in ray-finned fish and eutherian mammals. Several alternatively spliced OanTERT variants structurally similar to avian TERT variants were identified. Telomerase activity is expressed in all platypus tissues like that of cold-blooded animals and murine rodents. OanTERT was localized on pseudoautosomal regions of sex chromosomes X3/Y2, expanding the homology between human chromosome 5 and platypus sex chromosomes. Synteny analysis suggests that TERT co-localized with sex-linked genes in the last common mammalian ancestor. Interestingly, female platypuses express higher levels of telomerase in heart and liver tissues than do males.ConclusionsOanTERT shares many features with TERT of the reptilian outgroup, suggesting that OanTERT represents the ancestral mammalian TERT. Features specific to TERT of eutherian mammals have, therefore, evolved more recently after the divergence of monotremes.

【 授权许可】

Unknown   
© Hrdličková et al.; licensee BioMed Central Ltd. 2012. 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.