Telomeres are composed of TTAGGG repeats and located at the ends of chromosomes. Telomeres protect chromosomes from instability in mammals, including mice and humans. Repetitive TTAGGG sequences are also found at intr...Telomeres are composed of TTAGGG repeats and located at the ends of chromosomes. Telomeres protect chromosomes from instability in mammals, including mice and humans. Repetitive TTAGGG sequences are also found at intrachromosomal sites, where they are named as interstitial telomeric sequences （ITSs）. Aberrant ITSs are implicated in chromosomal instability and found in cancer cells. Interestingly, in pigs, vertebrate telomere sequences TTAGGG （vlTSs） are also localized at the centro- meric region of chromosome 6, in addition to the end of all chromosomes. Surprisingly, we found that botanic telomere se- quences, TTTAGGG （bITSs）, also localize with vITSs at the centromeric regions of pig chromosome 6 using telomere fluo- rescence in situ hybridization （FISH） and by comparisons between several species. Furthermore, the average lengths of vITSs are highly correlated with those of the terminal telomeres （TTS）. Also, pig ITSs show a high incidence of telomere doublets, suggesting that pig ITSs might be unstable and dynamic. Together, our results show that pig cells maintain the conserved te- lomere sequences that are found at the ITSs from of plants and other vertebrates. Further understanding of the function and regulation of pig ITSs may provide new clues for evolution and chromosomal instability.展开更多
基金supported by the National Basic Research Program of China(Grant Nos. 2009CB941000 and 2011CBA01002)
文摘Telomeres are composed of TTAGGG repeats and located at the ends of chromosomes. Telomeres protect chromosomes from instability in mammals, including mice and humans. Repetitive TTAGGG sequences are also found at intrachromosomal sites, where they are named as interstitial telomeric sequences （ITSs）. Aberrant ITSs are implicated in chromosomal instability and found in cancer cells. Interestingly, in pigs, vertebrate telomere sequences TTAGGG （vlTSs） are also localized at the centro- meric region of chromosome 6, in addition to the end of all chromosomes. Surprisingly, we found that botanic telomere se- quences, TTTAGGG （bITSs）, also localize with vITSs at the centromeric regions of pig chromosome 6 using telomere fluo- rescence in situ hybridization （FISH） and by comparisons between several species. Furthermore, the average lengths of vITSs are highly correlated with those of the terminal telomeres （TTS）. Also, pig ITSs show a high incidence of telomere doublets, suggesting that pig ITSs might be unstable and dynamic. Together, our results show that pig cells maintain the conserved te- lomere sequences that are found at the ITSs from of plants and other vertebrates. Further understanding of the function and regulation of pig ITSs may provide new clues for evolution and chromosomal instability.
