title: valentino: a zebrafish gene required for normal hindbrain segmentation.
abstract: Mutational analysis can serve both to identify new genes essential for patterning embryonic development and to determine their functions. Here we describe the identification and phenotypic characterization of alleles of valentino, which we recovered in a genetic screen that sought to identify mutations in the zebrafish that disrupt region-specific gene expression patterns in the embryonic brain. valentino is required for normal hindbrain segmentation and the hindbrain of valentino mutant embryos is shortened by the length of one rhombomere. We demonstrate that valentino is required cell-autonomously in the development of rhombomeres 5 and 6, and propose that valentino functions in the subdivision and expansion of a common precursor region in the presumptive hindbrain into the definitive rhombomeres 5 and 6. These results provide genetic evidence for a two-segment periodicity in the hindbrain and suggest that this periodicity arises sequentially, through the specification and later subdivision of a two-rhombomere unit, or 'protosegment'.
authors.affiliation: Institute of Neuroscience, University of Oregon, Eugene 97403-1254, USA. moens@uoneuro.uoregon.edu
authors.forename: C B
authors.initials: CB
authors.lastname: Moens
authors.forename: Y L
authors.initials: YL
authors.lastname: Yan
authors.forename: B
authors.initials: B
authors.lastname: Appel
authors.forename: A G
authors.initials: AG
authors.lastname: Force
authors.forename: C B
authors.initials: CB
authors.lastname: Kimmel
mesh_terms: D000818:Animals; D030161:Avian Proteins; D019521:Body Patterning / Q000235:genetics*; D017690:Cell Transplantation; D004268:DNA-Binding Proteins / Q000235:genetics; D005819:Genetic Markers; D017403:In Situ Hybridization; D050977:Maf Transcription Factors; D008954:Models, Biological; D009030:Mosaicism; D015513:Oncogene Proteins; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000302:isolation & purification; D012249:Rhombencephalon / Q000033:anatomy & histology / Q000196:embryology*; D012641:Selection, Genetic; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics; D015027:Zebrafish / Q000196:embryology; D029961:Zebrafish Proteins
chemical_list: D030161:Avian Proteins; D004268:DNA-Binding Proteins; D005819:Genetic Markers; D050977:Maf Transcription Factors; D015513:Oncogene Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D029961:Zebrafish Proteins; C490408:mafbb protein, zebrafish