Transcriptional regulation of human polo-like kinases and early mitotic inhibitor.
Human polo-like kinases (PLK1-PLK4) have been implicated in mitotic regulation and carcinogenesis. PLK1 phosphorylates early mitotic inhibitor 1 (Emi1) to ensure mitosis entry, whereas Emi2 plays a key role during the meiotic cell cycle. Transcription factor E2F is primarily considered to regulate the G(1)/S transition of the cell cycle but its involvement in the regulation of mitosis has also been recently suggested. A gap still exists between the molecular basis of E2F and mitotic regulation. The present study was designed to characterize the transcriptional regulation of human PLK and Emi genes. Adenoviral overexpression of E2F1 increased PLK1 and PLK3 mRNA levels in A549 cells. A reporter gene assay revealed that the putative promoter regions of PLK1, PLK3, and PLK4 genes were responsive to activators E2F, E2F1-E2F3. We further characterized the putative promoter regions of Emi1 and Emi2 genes, and these could be regulated by activators E2F and E2F1-E2F4, respectively. Finally, PLK1-PLK4, Emi1, and Emi2 mRNA expression levels in human adult, fetal tissues, and several cell lines indicated that each gene has a unique expression pattern but is uniquely expressed in common tissues and cells such as the testes and thymus. Collectively, these results indicate that E2F can integrate G(1)/S and G(2)/M to oscillate the cell cycle by regulating mitotic genes PLK and Emi, leading to determination of the cell fate.
Tategu
Moe
M
Department of Life Sciences, Meiji University School of Agriculture, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan.
Nakagawa
Hiroki
H
Sasaki
Kaori
K
Yamauchi
Rieko
R
Sekimachi
Sota
S
Suita
Yuka
Y
Watanabe
Naoko
N
Yoshid
Kenichi
K
D000818:Animals; D002453:Cell Cycle / Q000235:genetics; D018797:Cell Cycle Proteins / Q000235:genetics*; D002454:Cell Differentiation; D002460:Cell Line; D050687:E2F1 Transcription Factor / Q000235:genetics / Q000378:metabolism; D044783:F-Box Proteins / Q000235:genetics*; D006801:Humans; D011401:Promoter Regions, Genetic / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D015854:Up-Regulation
D018797:Cell Cycle Proteins; D050687:E2F1 Transcription Factor; D044783:F-Box Proteins; C533792:FBXO43 protein, human; C498960:FBXO5 protein, human; D012333:RNA, Messenger; D017346:Protein Serine-Threonine Kinases