Telomeres and telomerase activity in pig tissues

Fradiani, Pier Assunta; Ascenzioni, Fiorentina; Lavitrano, Marialuisa; Donini, Pierluigi

doi:10.1016/j.biochi.2003.11.009

Cited by 50 publications

(50 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Serial cloning, thus, did not cause telomere shortening. The telomere length of each cloned pig was within the previously reported normal ranges for pigs [46][47][48].…”

Section: Telomere Length Analysis In Cloned Pigs Produced By Serial Nsupporting

confidence: 76%

“…Serial cloning, thus, did not cause telomere shortening. The telomere length of each cloned pig was within the previously reported normal ranges for pigs [46][47][48].In recent years, studies have measured telomere length in cloned animals and reported that compared with age-matched controls, the telomere lengths of cloned animals are shorter [19][20][21][22][23][24], comparable [6,[48][49][50] or longer [5,20,51,52]. As a result, no clear conclusions have been reached regarding the issue of telomere length in cloned animals.…”

mentioning

confidence: 51%

See 1 more Smart Citation

Production Efficiency and Telomere Length of the Cloned Pigs Following Serial Somatic Cell Nuclear Transfer

Kurome

Higuchi

Matsumoto

et al. 2008

Journal of Reproduction and Development

View full text Add to dashboard Cite

Abstract. The aim of the present study was to examine the production efficiency of cloned pigs by serial somatic cell nuclear transfer (SCNT) and to ascertain any changes in the telomere lengths of multiple generations of pigs. Using fetal fibroblasts as the starting nuclear donor cells, porcine salivary gland progenitor cells were collected from the resultant first-generation cloned pigs to successively produce second-and third-generation clones, with no significant differences in production efficiency, which ranged from 1.4% (2/140) to 3.3% (13/391) among the 3 generations. The average telomere lengths (terminal restriction fragment values) for the first, second and third generation clones were 16.3, 18.1 and 20.5 kb, respectively, and were comparable to those in age-matched controls. These findings suggest that thirdgeneration cloned pigs can be produced by serial somatic cell cloning without compromising production efficiency and that the telomere lengths of cloned pigs from the first to third generations are normal. Key words: Aging, Pig cloning, Progenitor cell, Somatic cell nuclear transfer (SCNT), Telomere (J. Reprod. Dev. 54: [254][255][256][257][258] 2008) ince the birth of the first cloned sheep, more than 10 animal species have been cloned by SCNT [1]. However, various questions and problems remain with regard to production of somatic cell clones and practical application of cloning techniques. For example, abnormal development of cloned fetuses, anatomical abnormality of cloned offspring, postpartum mortality and low production efficiency of healthy clones are problems commonly encountered with all animal species [2][3][4].Somatic cell cloning comprises replication of an individual animal. It is of considerable biological significance to ascertain the capability of SCNT technology in producing multiple generations of clones, namely, sequential cloning of cloned animals. To date, mice have been cloned up to six generations [5], while cows have been cloned up to two generations [6].Serial cloning of pigs has practical implications in producing genetically engineered animals. Genetically modified pigs such as alpha 1,3-galactosyltransferase-knockout pigs [7][8][9][10][11][12][13][14] and those with a n-3 fatty acid desaturase gene [15] have been produced using serial cloning technology. In this context, multiple generations of clones up to the third generation have been reported in pigs [16,17]. On the other hand, studies have found that serial cloning causes the accumulation of epigenetic modifications that result from the SCNT procedure [3,18]. Indeed, the production efficiency of clones has been reported to decrease as the number of serial clonings increases [5,6,17].Telomere shortening is another form of genetic modification resulting from the somatic cell cloning procedure [19][20][21][22][23][24]. However, serial somatic cell cloning has been shown to not cause telomere shortening in mice [5] and cows [6]. The changes in telomere length involved in serial pig cloning have yet to be determined....

show abstract

“…Serial cloning, thus, did not cause telomere shortening. The telomere length of each cloned pig was within the previously reported normal ranges for pigs [46][47][48].…”

Section: Telomere Length Analysis In Cloned Pigs Produced By Serial Nsupporting

confidence: 76%

mentioning

confidence: 51%

Production Efficiency and Telomere Length of the Cloned Pigs Following Serial Somatic Cell Nuclear Transfer

Kurome

Higuchi

Matsumoto

et al. 2008

Journal of Reproduction and Development

View full text Add to dashboard Cite

show abstract

“…Pig telomeres have lengths similar to other ungulates, ranging in size from 10 to 30 kb (Fradiani et al, 2004;Jeon et al, 2005). However, two reports indicate that multiple pig somatic tissues such as lymph nodes, lung, kidney, and small intestine retain significant levels of telomerase activity (Wong et al, 2003;Fradiani et al, 2004). During in vitro culture pig fibroblasts enter a period of slow growth associated with appearance of senescent markers, after which immortal cells emerge and resume rapid growth (Oh et al, 2007).…”

Section: Ungulatesmentioning

confidence: 99%

Coevolution of telomerase activity and body mass in mammals: From mice to beavers

Gorbunova

Seluanov

2009

Mechanisms of Ageing and Development

102

View full text Add to dashboard Cite

Telomerase is repressed in the majority of human somatic tissues. As a result human somatic cells undergo replicative senescence, which plays an important role in suppressing tumorigenesis, and at the same time contributes to the process of aging. Repression of somatic telomerase activity is not a universal phenomenon among mammals. Mice, for example, express telomerase in somatic tissues, and mouse cells are immortal when cultured at physiological oxygen concentration. What is the status of telomerase in other animals, beyond human and laboratory mouse, and why do some species evolve repression of telomerase activity while others do not? Here we discuss the data on telomere biology in various mammalian species, and a recent study of telomerase activity in a large collection of wild rodent species, which showed that telomerase activity coevolves with body mass, but not lifespan. Large rodents repress telomerase activity, while small rodents maintain high levels of telomerase activity in somatic cells. We discuss a model that large body mass presents an increased cancer risk, which drives the evolution of telomerase suppression and replicative senescence.

show abstract

“…Pig telomeres had conserved (TTAGGG) n repeats as reported in other vertebrates [31,42]. Most plants have (TTTAGGG) n repeats as found, for example, in Arabidopsis telomeres [3,4].…”

Section: Discussionmentioning

confidence: 76%

Conservation and characterization of unique porcine interstitial telomeric sequences

Chen

et al. 2012

Sci. China Life Sci.

View full text Add to dashboard Cite

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 (vITSs) are also localized at the centromeric region of chromosome 6, in addition to the end of all chromosomes. Surprisingly, we found that botanic telomere sequences, TTTAGGG (bITSs), also localize with vITSs at the centromeric regions of pig chromosome 6 using telomere fluorescence 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 telomere 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. evolution, telomere, interstitial telomeric sequence (ITS), pig Citation:Ji G Z, Liu K, Chen C B, et al. Conservation and characterization of unique porcine interstitial telomeric sequences. Sci China Life Sci, 2012Sci, , 55: 1029Sci, -1037Sci, , doi: 10.1007 Telomeres are located at the ends of liner chromosomes, protecting chromosomes from instability [1]. The telomeric hexanucleotide (TTAGGG) n repeat sequence is conserved in a wide range of species from invertebrates, including fish, amphibian and reptiles, to vertebrates, including mouse, human and pig [2], whereas the telomeric repeat of most plants is the heptanucleotide TTTAGGG [3,4]. The (TTAGGG) n repeat is also found at intrachromosomal sites, including those repeats located close to the centromeres, and at interstitial sites, namely, the sites between the centromeres and telomeres, in which case the repeats are called interstitial telomeric sequences (ITSs) [5][6][7].

show abstract

Telomeres and telomerase activity in pig tissues

Cited by 50 publications

References 33 publications

Production Efficiency and Telomere Length of the Cloned Pigs Following Serial Somatic Cell Nuclear Transfer

Production Efficiency and Telomere Length of the Cloned Pigs Following Serial Somatic Cell Nuclear Transfer

Coevolution of telomerase activity and body mass in mammals: From mice to beavers

Conservation and characterization of unique porcine interstitial telomeric sequences

Contact Info

Product

Resources

About