title: Characterization of the telomere complex, TERF1 and TERF2 genes in muntjac species with fusion karyotypes.
abstract: The telomere binding proteins TRF1 and TRF2 maintain and protect chromosome ends and confer karyotypic stability. Chromosome evolution in the genus Muntiacus is characterized by numerous tandem (end-to-end) fusions. To study TRF1 and TRF2 telomere binding proteins in Muntiacus species, we isolated and characterized the TERF1 and -2 genes from Indian muntjac (Muntiacus muntjak vaginalis; 2n = 6 female) and from Chinese muntjac (Muntiacus reveesi; 2n = 46). Expression analysis revealed that both genes are ubiquitously expressed and sequence analysis identified several transcript variants of both TERF genes. Control experiments disclosed a novel testis-specific splice variant of TERF1 in human testes. Amino acid sequence comparisons demonstrate that Muntiacus TRF1 and in particular TRF2 are highly conserved between muntjac and human. In vivo TRF2-GFP and immuno-staining studies in muntjac cell lines revealed telomeric TRF2 localization, while deletion of the DNA binding domain abrogated this localization, suggesting muntjac TRF2 represents a functional telomere protein. Finally, expression analysis of a set of telomere-related genes revealed their presence in muntjac fibroblasts and testis tissue, which suggests the presence of a conserved telomere complex in muntjacs. However, a deviation from the common theme was noted for the TERT gene, encoding the catalytic subunit of telomerase; TERT expression could not be detected in Indian or Chinese muntjac cDNA or genomic DNA using a series of conserved primers, while TRAP assay revealed functional telomerase in Chinese muntjac testis tissues. This suggests muntjacs may harbor a diverged telomerase sequence.
authors.affiliation: Max Planck Institute for Molecular Genetics, Ihnestr. 73, D-14195 Berlin, Germany.
authors.forename: Nils
authors.initials: N
authors.lastname: Hartmann
authors.forename: Harry
authors.initials: H
authors.lastname: Scherthan
mesh_terms: D017398:Alternative Splicing / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D033481:Chromosomes, Mammalian / Q000235:genetics; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D015870:Gene Expression / Q000235:genetics; D006801:Humans; D007621:Karyotyping; D051379:Mice; D008969:Molecular Sequence Data; D018668:Muntjacs / Q000235:genetics* / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D019098:Telomerase / Q000235:genetics; D016615:Telomere / Q000378:metabolism*; D035321:Telomeric Repeat Binding Protein 1 / Q000235:genetics* / Q000378:metabolism; D035341:Telomeric Repeat Binding Protein 2 / Q000235:genetics* / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D009687:Nuclear Proteins; D020033:Protein Isoforms; D035321:Telomeric Repeat Binding Protein 1; D035341:Telomeric Repeat Binding Protein 2; D019098:Telomerase