title: KLF6 is one transcription factor involved in regulating acid ceramidase gene expression.
abstract: Acid ceramidase (AC; E.C.3.5.1.23) activity is required to hydrolyze ceramide into sphingosine. An inherited deficiency of this enzymatic activity leads to the lipid storage disorder, Farber Lipogranulomatosis. Aberrant AC activity also has been demonstrated in several human cancers. We have characterized a 1931-bp putative promoter region of the murine AC gene by Luciferase reporter assays, electrophoretic mobility shift assays, and mutational analysis. A 143-bp sequence essential for AC promoter activity was found, and mobility shift and super-shift experiments using nuclear extracts of NIH3T3 cells demonstrated that a 34-bp, GC-rich sub-region could bind the transcription factors KLF6, Sp1, and AP2. Transient over-expression of KLF6 in NIH3T3 cells significantly increased the activity of a co-transfected Luciferase reporter construct containing the wild-type AC promoter, and a positive correlation was observed between AC and KFL6 RNA and protein expression in two different human cancer cell lines in which KLF6 expression was either "knocked-down" by RNAi or increased by retroviral-mediated gene transfer. Northern blot analysis also revealed a correlation of KLF6 and AC gene expression in various human tissues. These results provide the first characterization of the AC promoter from any species and demonstrate that KLF6 is one transcription factor involved in the regulation of AC gene expression.
authors.affiliation: Departments of Human Genetics, Mount Sinai School of Medicine, 1425 Madison Avenue, New York, NY 10029, USA.
authors.forename: Jae-Ho
authors.initials: JH
authors.lastname: Park
authors.forename: Efrat
authors.initials: E
authors.lastname: Eliyahu
authors.forename: Goutham
authors.initials: G
authors.lastname: Narla
authors.forename: Analisa
authors.initials: A
authors.lastname: DiFeo
authors.forename: John A
authors.initials: JA
authors.lastname: Martignetti
authors.forename: Edward H
authors.initials: EH
authors.lastname: Schuchman
mesh_terms: D000818:Animals; D015153:Blotting, Western; D045744:Cell Line, Tumor; D024202:Electrophoretic Mobility Shift Assay; D005091:Exons / Q000235:genetics; D002517:Galactosylgalactosylglucosylceramidase / Q000235:genetics*; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic; D017930:Genes, Reporter; D006801:Humans; D000075723:Kruppel-Like Factor 6; D051741:Kruppel-Like Transcription Factors / Q000235:genetics*; D051379:Mice; D041681:NIH 3T3 Cells; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: C105465:KLF6 protein, human; C491358:Klf6 protein, mouse; D000075723:Kruppel-Like Factor 6; D051741:Kruppel-Like Transcription Factors; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D002517:Galactosylgalactosylglucosylceramidase