| First Author | Lee DK | Year | 1994 |
| Journal | Mol Reprod Dev | Volume | 39 |
| Issue | 3 | Pages | 259-67 |
| PubMed ID | 7888165 | Mgi Jnum | J:21204 |
| Mgi Id | MGI:69235 | Doi | 10.1002/mrd.1080390303 |
| Citation | Lee DK, et al. (1994) Analysis of thymidine kinase gene expression in preimplantation mouse embryos. Mol Reprod Dev 39(3):259-67 |
| abstractText | Thymidine kinase (TK) activity was examined during the development of preimplantation mouse embryos. TK activity was increased approximately 20-fold from day 2 embryos (2-cell) to day 5 embryos (late blastocyst). TK activity did not change along with the progression into S-phase of the first and the second cell cycles but increased sharply at S-phase of the third cell cycle. Analysis of TK mRNA with a reverse transcription-polymerase chain reaction (RT-PCR) method showed that the level of TK mRNA was low in ovulated eggs and 1-cell embryos and was hardly detectable in day 2 embryos (2-cell), but sharply increased in day 3 embryos (mixture of 5- to 8-cell and morula). The functional role of 5'-flanking sequence of TK gene was also investigated in preimplantation embryos after microinjection with the DNA construct of 5'-flanking sequence of TK (2.4 kb) linked to bacterial lacZ gene (TK2.5lacZ) into the pronucleus of 1-cell and subsequently by histochemical staining with X-gal. beta-Galactosidase activity was first detected in day 3 embryos (8-cell), and 30% of embryos were stained with X-gal in day 4 and day 5 embryos, respectively. These results show that an increase in TK activity occurred after 2-cell stage, and this increase was primarily due to the embryonic activation of TK gene expression. Also, it appears that the 5'-flanking sequence of TK may directly regulate the TK gene expression at the transcriptional level during preimplantation murine development. |
