title: dNF-YB plays dual roles in cell death and cell differentiation during Drosophila eye development.
abstract: Nuclear transcription factor Y (NF-Y) is well characterized in eukaryotes. It consists of three different subunits, NF-YA, NF-YB and NF-YC, all of which are required for formation of the NF-Y complex and DNA-binding. There is a high homology in NF-YB among Drosophila species with 75% identity and 95% similarity overall, especially in the histone-fold motif (HFM) (95% identity and 100% similarity). In the present study, specific knockdown of Drosophila NF-YB (dNF-YB) in eye imaginal discs induced a rough eye phenotype in adults and this phenotype was the result of induction of caspase-dependent apoptosis followed by apoptosis-induced proliferation. Furthermore, knockdown specifically inhibited R7 photoreceptor cell differentiation, independent of the apoptotic function. dNF-YB and dNF-YA indeed form complexes in vivo where they impair R7 photoreceptor cell differentiation by down regulating the mitogen-activated protein kinase (MAPK) pathway. Expression of the sev gene, or the D-raf gene, a downstream component of the MAPK cascade, could rescue the rough eye phenotype and the loss of R7 signals in dNF-YB knockdown flies. The death executioner Bcl-2 (debcl) is the homolog of Bcl-2 in Drosophila melanogaster and its promoter contains four dNF-Y-binding consensus sequences which play positive roles in promoter activity. In chromatin immunoprecipitation assays with anti-dNF-YB antibody and S2 cells, the debcl gene promoter region containing the NF-Y consensus was effectively amplified in immunoprecipitates by polymerase chain reaction. Taken together, these results indicate that dNF-Y regulates debcl gene expression.
authors.affiliation: Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Kyoto 606-8585, Japan.
authors.forename: Luong Linh
authors.initials: LL
authors.lastname: Ly
authors.forename: Osamu
authors.initials: O
authors.lastname: Suyari
authors.forename: Yasuhide
authors.initials: Y
authors.lastname: Yoshioka
authors.forename: Nguyen Trong
authors.initials: NT
authors.lastname: Tue
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshida
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Yamaguchi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D023081:CCAAT-Binding Factor / Q000235:genetics / Q000502:physiology*; D016923:Cell Death / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics*; D002460:Cell Line; D004331:Drosophila melanogaster / Q000196:embryology* / Q000235:genetics; D004625:Embryo, Nonmammalian; D005123:Eye / Q000196:embryology* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D008969:Molecular Sequence Data; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D017385:Sequence Homology; D014162:Transfection
chemical_list: D023081:CCAAT-Binding Factor; D019253:Proto-Oncogene Proteins c-bcl-2