The Sp family of transcription factors regulates the human laminin alpha1 gene in JAR choriocarcinoma cells.
Laminin-111 (alpha1beta1gamma1) is the major component of the embryonic and extra-embryonic basement membrane. The laminin alpha1 chain shows a restricted and developmentally regulated expression in basement membranes of distinct epithelial tissues while beta1 and gamma1 chains have a wide tissue distribution. To understand how human laminin alpha1 chain expression is controlled, we cloned and characterized the 5'-flanking region of the human laminin alpha1 (LAMA1) gene. Transfection studies using serially deleted promoter constructs and JAR choriocarcinoma cells revealed that the minimal promoter fragment resided in the +31 to -206 region, which contains a number of GC- and GT/A-rich motifs for the binding of the Sp family of transcription factors. Electrophoretic mobility shift assays and mutational analyses revealed that Sp1 and Sp3 bound specifically to these elements and are important for the promoter activity. Furthermore, we showed that Krüppel-like factors KLF4 and KLF6 also activate transcription of the human LAMA1 gene. Chromatin immunoprecipitation analysis demonstrated recruitment of these transcription factors to the promoter region. These results indicate that transcription of the human LAMA1 gene is controlled by a combination of the actions of Sp1/Sp3 and Krüppel-like factors, KLF4 and KLF6.
Niimi
Tomoaki
T
Department of Bioengineering Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya 464-8601, Japan. tniimi@agr.nagoya-u.ac.jp
Hayashi
Yoshitaka
Y
Sekiguchi
Kiyotoshi
K
Kitagawa
Yasuo
Y
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D045744:Cell Line, Tumor; D002822:Choriocarcinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D047369:Chromatin Immunoprecipitation; D024202:Electrophoretic Mobility Shift Assay; D015972:Gene Expression Regulation, Neoplastic; D006367:HeLa Cells; D006801:Humans; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism; D007797:Laminin / Q000235:genetics*; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D009841:Oligonucleotides / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D051705:Sp3 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
C000715467:KLF4 protein, human; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D007797:Laminin; D009841:Oligonucleotides; D011993:Recombinant Fusion Proteins; D016329:Sp1 Transcription Factor; D051705:Sp3 Transcription Factor; C084098:laminin A; D008156:Luciferases