TY - JOUR
T1 - Self-renewal of human embryonic stem cells is supported by a shortened G1 cell cycle phase
AU - Becker, Klaus A.
AU - Ghule, Prachi N.
AU - Therrien, Jaclyn A.
AU - Lian, Jane B.
AU - Stein, Janet L.
AU - Van Wijnen, Andre J.
AU - Stein, Gary S.
PY - 2006/12
Y1 - 2006/12
N2 - Competency for self-renewal of human embryonic stem (ES) cells is linked to pluripotency. However, there is a critical paucity of fundamental parameters of human ES cell division. In this study we show that human ES cells (H1 and H9; NIH-designated WA01 and WA09) rapidly proliferate due to a very short overall cell cycle (15-1 6 h) compared to somatic cells (e.g., normal diploid IMR90 fibroblasts and NT-2 teratocarcinoma cells). The human ES cell cycle maintains the four canonical cell cycle stages G1, S, G2, and M, but the duration of G1 is dramatically shortened. Bromodeoxyuridine(BrdU) incorporation and FACS analysis demonstrated that 65% of asynchronously growing human ES cells are in S phase. Immunofluorescence microscopy studies detecting BrdU labeled mitotic chromosomes, Ki67 domains, and p220NPAT containing Cajal bodies revealed that the durations of the S (∼8 h), G2 (∼4 h), and M phases (∼1 h) are similar in ES and somatic cells. We determined that human ES cells remain viable after synchronization with either nocodazole or the anti-tumor drug Paclitaxel (taxol) and have an abbreviated G1 phase of only 2.5-3 h that is significantly shorter than in somatic cells. Molecular analyses using quantitative RT-PCR demonstrate that human ES cells and somatic cells express similar cell cycle markers. However, among cyclins and cyclin-dependent kinases (CDKs), we observed high mRNA levels for the G1-related CDK4 and cyclin D2 genes. We conclude that human ES cells exhibit unique G1 cell cycle kinetics and useCDK4/cyclin D2 related mechanisms to attain competency for DNA replication.
AB - Competency for self-renewal of human embryonic stem (ES) cells is linked to pluripotency. However, there is a critical paucity of fundamental parameters of human ES cell division. In this study we show that human ES cells (H1 and H9; NIH-designated WA01 and WA09) rapidly proliferate due to a very short overall cell cycle (15-1 6 h) compared to somatic cells (e.g., normal diploid IMR90 fibroblasts and NT-2 teratocarcinoma cells). The human ES cell cycle maintains the four canonical cell cycle stages G1, S, G2, and M, but the duration of G1 is dramatically shortened. Bromodeoxyuridine(BrdU) incorporation and FACS analysis demonstrated that 65% of asynchronously growing human ES cells are in S phase. Immunofluorescence microscopy studies detecting BrdU labeled mitotic chromosomes, Ki67 domains, and p220NPAT containing Cajal bodies revealed that the durations of the S (∼8 h), G2 (∼4 h), and M phases (∼1 h) are similar in ES and somatic cells. We determined that human ES cells remain viable after synchronization with either nocodazole or the anti-tumor drug Paclitaxel (taxol) and have an abbreviated G1 phase of only 2.5-3 h that is significantly shorter than in somatic cells. Molecular analyses using quantitative RT-PCR demonstrate that human ES cells and somatic cells express similar cell cycle markers. However, among cyclins and cyclin-dependent kinases (CDKs), we observed high mRNA levels for the G1-related CDK4 and cyclin D2 genes. We conclude that human ES cells exhibit unique G1 cell cycle kinetics and useCDK4/cyclin D2 related mechanisms to attain competency for DNA replication.
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U2 - 10.1002/jcp.20776
DO - 10.1002/jcp.20776
M3 - Article
C2 - 16972248
AN - SCOPUS:33750524413
SN - 0021-9541
VL - 209
SP - 883
EP - 893
JO - Journal of Cellular Physiology
JF - Journal of Cellular Physiology
IS - 3
ER -