Chromosomal and telomeric reprogramming following ES-somatic cell fusion.
Chromosomal and telomeric reprogramming was assessed in intraspecies hybrids obtained by fusion of embryonic stem (ES) cells and mouse embryonic fibroblasts. Evaluation of the ploidy of ES-somatic hybrids revealed that 21 of 59 clones had a tetraploid DNA profile while the remaining clones showed deviations from the expected profile of fusion between two diploid cells. Microsatellite polymerase chain reaction analysis of four of these clones demonstrated no random loss of somatic chromosome pairs in the ES-somatic cell hybrids. Pluripotential of ES-somatic hybrids was assessed by gene expression analysis, antibody staining for Oct4 and SSEA-1 and teratoma formation containing derivatives of the three germ layers. Reprogramming of telomeric maintenance was observed with ES-somatic hybrids showing high telomerase activity and increased telomere lengths. However, we detected no significant increase in the expression of the three critical telomerase subunits: telomerase reverse transcriptase (TERT), telomerase RNA component (TERC), and dyskerin. This indicates that activation of telomerase and telomere maintenance is not reliant on changes in gene expression of TERT, TERC, and dyskerin following ES-somatic cell fusion or sister chromatid recombination and may arise through elimination of negative regulation of telomerase activity. This is the first demonstration of telomere lengthening following cell fusion and offers a new model for studying and identifying new regulators of telomere maintenance.
Sumer
Huseyin
H
Monash Institute of Medical Research, Monash University, 27-31 Wright Street, Clayton, Victoria, 3168, Australia. huseyin.sumer@med.monash.edu.au
Nicholls
Craig
C
Pinto
Alexander R
AR
Indraharan
Dinesh
D
Liu
Jun
J
Lim
Mei Ling
ML
Liu
Jun-Ping
JP
Verma
Paul J
PJ
D000818:Animals; D018929:Cell Culture Techniques; D018797:Cell Cycle Proteins / Q000096:biosynthesis / Q000235:genetics; D002459:Cell Fusion; D002460:Cell Line; D020090:Chromosome Segregation; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000502:physiology; D005347:Fibroblasts / Q000166:cytology* / Q000502:physiology; D005786:Gene Expression Regulation; D006822:Hybrid Cells; D016256:Lewis X Antigen / Q000378:metabolism; D051379:Mice; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics; D050814:Octamer Transcription Factor-3 / Q000378:metabolism; D011003:Ploidies; D012313:RNA / Q000096:biosynthesis / Q000235:genetics; D019098:Telomerase / Q000096:biosynthesis / Q000235:genetics; D016615:Telomere / Q000235:genetics*
D018797:Cell Cycle Proteins; C510431:Dkc1 protein, mouse; D016256:Lewis X Antigen; D009687:Nuclear Proteins; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; C422952:telomerase RNA; D012313:RNA; D019098:Telomerase; C509187:Tert protein, mouse