title: Thyrotroph embryonic factor regulates light-induced transcription of repair genes in zebrafish embryonic cells.
abstract: Numerous responses are triggered by light in the cell. How the light signal is detected and transduced into a cellular response is still an enigma. Each zebrafish cell has the capacity to directly detect light, making this organism particularly suitable for the study of light dependent transcription. To gain insight into the light signalling mechanism we identified genes that are activated by light exposure at an early embryonic stage, when specialised light sensing organs have not yet formed. We screened over 14,900 genes using micro-array GeneChips, and identified 19 light-induced genes that function primarily in light signalling, stress response, and DNA repair. Here we reveal that PAR Response Elements are present in all promoters of the light-induced genes, and demonstrate a pivotal role for the PAR bZip transcription factor Thyrotroph embryonic factor (Tef) in regulating the majority of light-induced genes. We show that tefbeta transcription is directly regulated by light while transcription of tefalpha is under circadian clock control at later stages of development. These data leads us to propose their involvement in light-induced UV tolerance in the zebrafish embryo.
authors.affiliation: Genomics Core Unit, European Molecular Biology Laboratory, Heidelberg, Federal Republic of Germany.
authors.forename: Daria
authors.initials: D
authors.lastname: Gavriouchkina
authors.forename: Sabine
authors.initials: S
authors.lastname: Fischer
authors.forename: Tomi
authors.initials: T
authors.lastname: Ivacevic
authors.forename: Jens
authors.initials: J
authors.lastname: Stolte
authors.forename: Vladimir
authors.initials: V
authors.lastname: Benes
authors.forename: Marcus P S
authors.initials: MP
authors.lastname: Dekens
mesh_terms: D000818:Animals; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism*; D004249:DNA Damage; D004260:DNA Repair / Q000528:radiation effects*; D018507:Gene Expression Regulation, Developmental / Q000528:radiation effects; D055537:Light Signal Transduction / Q000528:radiation effects; D011401:Promoter Regions, Genetic / Q000528:radiation effects; D020218:Response Elements / Q000528:radiation effects; D014158:Transcription, Genetic / Q000528:radiation effects; D014466:Ultraviolet Rays; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; D029961:Zebrafish Proteins; C489492:tefa protein, zebrafish