ISSN:
1040-452X
Keywords:
Thymidine kinase
;
Preimplantation mouse embryos
;
Embryonic gene expression
;
Cell cycle
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
Notes:
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 embryo (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. β-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. © 1994 Wiley-Liss, Inc.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrd.1080390303
