In vivo analysis of the cyclin D1 promoter during early embryogenesis in Xenopus.
Cyclin D1 plays an important role in the regulation of G1 progression of the somatic cell cycle by functioning as a regulatory subunit of cdk4 and 6. Since both cyclin D1-mRNA and -protein turn over very rapidly, the expression of cyclin D1 is mostly regulated at the transcription level. Detection of the cyclin D1-specific mRNA during early embryogenesis in Xenopus laevis revealed that expression was induced soon after the midblastula stage but not during the cleavage stage, and was mainly found in the neural plate and eye vesicles. The recently-developed transgenic frog technique enabled us to analyze the frog cyclin D1 promoter activity in vivo by using green fluorescent protein (GFP) as a marker. During early embryogenesis, a GFP signal was detected at the neural plate in the neurula of the transgenic embryos. Transgenic analysis using sequential-deletion and point mutants of the cyclin D1 promoter revealed that a single, putative TCF/LEF binding site, located approximately 3.5 kb upstream of the transcriptional initiation site, was required for neural plate-specific expression. Our results suggest that the TCF/LEF signaling pathway participates in the regulation of cyclin D1 induction during the generation of the dorsal nervous system in early frog embryogenesis.
Tanaka
Toshiaki
T
Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0101, Japan.
Kubota
Makoto
M
Shinohara
Kazufumi
K
Yasuda
Kunio
K
Kato
Jun-ya
JY
D020816:Amino Acid Motifs; D000818:Animals; D030801:Animals, Genetically Modified; D019938:Cyclin D1 / Q000235:genetics* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D006801:Humans; D009024:Morphogenesis / Q000502:physiology; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D014981:Xenopus / Q000196:embryology* / Q000235:genetics
D011994:Recombinant Proteins; D019938:Cyclin D1