valentino: a zebrafish gene required for normal hindbrain segmentation.

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'.

[1]  R. Krumlauf,et al.  Segmental expression of Hoxa-2 in the hindbrain is directly regulated by Krox-20. , 1996, Development.

[2]  M. Allende,et al.  Developmental regulation of zebrafish MyoD in wild-type, no tail and spadetail embryos. , 1996, Development.

[3]  J. Postlethwait,et al.  Expression of snail2, a second member of the zebrafish snail family, in cephalic mesendoderm and presumptive neural crest of wild-type and spadetail mutant embryos. , 1995, Developmental biology.

[4]  R. Toyama,et al.  The LIM class homeobox gene lim5: implied role in CNS patterning in Xenopus and zebrafish. , 1995, Developmental biology.

[5]  S. Fraser,et al.  Order and coherence in the fate map of the zebrafish nervous system. , 1995, Development.

[6]  C. Kimmel,et al.  Stages of embryonic development of the zebrafish , 1995, Developmental dynamics : an official publication of the American Association of Anatomists.

[7]  S. Guthrie.  The status of the neural segment , 1995, Trends in Neurosciences.

[8]  G. Barsh,et al.  The mouse segmentation gene kr encodes a novel basic domain-leucine zipper transcription factor , 1994, Cell.

[9]  R. Krumlauf,et al.  The kreisler mouse: a hindbrain segmentation mutant that lacks two rhombomeres. , 1994, Development.

[10]  M. Westerfield,et al.  Neural selective activation and temporal regulation of a mammalian GAP-43 promoter in zebrafish. , 1994, Development.

[11]  M. Westerfield,et al.  Combinatorial expression of three zebrafish genes related to distal- less: part of a homeobox gene code for the head , 1994, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[12]  E. Birgbauer,et al.  Violation of cell lineage restriction compartments in the chick hindbrain. , 1994, Development.

[13]  J. Postlethwait,et al.  A genetic linkage map for the zebrafish. , 1994, Science.

[14]  A. Schier,et al.  Efficient recovery of ENU-induced mutations from the zebrafish germline. , 1994, Genetics.

[15]  Stephen W. Wilson,et al.  Spatially regulated expression of three receptor tyrosine kinase genes during gastrulation in the zebrafish. , 1994, Development.

[16]  C. Kimmel,et al.  Cell cycles and clonal strings during formation of the zebrafish central nervous system. , 1994, Development.

[17]  R. Krumlauf,et al.  Hox genes and regionalization of the nervous system. , 1994, Annual review of neuroscience.

[18]  P. Ingham,et al.  A functionally conserved homolog of the Drosophila segment polarity gene hh is expressed in tissues with polarizing activity in zebrafish embryos , 1993, Cell.

[19]  S. Schneider-Maunoury,et al.  Disruption of Krox-20 results in alteration of rhombomeres 3 and 5 in the developing hindbrain , 1993, Cell.

[20]  P. Swiatek,et al.  Perinatal lethality and defects in hindbrain development in mice homozygous for a targeted mutation of the zinc finger gene Krox20. , 1993, Genes & development.

[21]  C. Wright.  Hox genes and the hindbrain , 1993, Current Biology.

[22]  V. Prince,et al.  Selective dispersal of avian rhombomere cells in orthotopic and heterotopic grafts. , 1993, Development.

[23]  E. Oxtoby,et al.  Cloning of the zebrafish krox-20 gene (krx-20) and its expression during hindbrain development. , 1993, Nucleic acids research.

[24]  R. Krumlauf,et al.  The zinc finger gene Krox20 regulates HoxB2 (Hox2.8) during hindbrain segmentation , 1993, Cell.

[25]  M. Westerfield,et al.  Coordinate embryonic expression of three zebrafish engrailed genes. , 1992, Development.

[26]  S. Ben‐Sasson,et al.  Identification of programmed cell death in situ via specific labeling of nuclear DNA fragmentation , 1992, The Journal of cell biology.

[27]  A. Graham,et al.  Segmental origin and migration of neural crest cells in the hindbrain region of the chick embryo. , 1991, Development.

[28]  A. Lumsden,et al.  Formation and regeneration of rhombomere boundaries in the developing chick hindbrain. , 1991, Development.

[29]  R. Ho,et al.  Cell-autonomous action of zebrafish spt-1 mutation in specific mesodermal precursors , 1990, Nature.

[30]  W. K. Metcalfe,et al.  Primary neurons that express the L2/HNK-1 carbohydrate during early development in the zebrafish. , 1990, Development.

[31]  C. Kimmel,et al.  Organization of hindbrain segments in the zebrafish embryo , 1990, Neuron.

[32]  R. Krumlauf,et al.  Segmental expression of Hox-2 homoeobox-containing genes in the developing mouse hindbrain , 1989, Nature.

[33]  D. Wilkinson,et al.  Segment-specific expression of a zinc-finger gene in the developing nervous system of the mouse , 1989, Nature.

[34]  R. Keynes,et al.  Segmental patterns of neuronal development in the chick hindbrain , 1989, Nature.

[35]  M. Westerfield,et al.  Segmental pattern of development of the hindbrain and spinal cord of the zebrafish embryo. , 1988, Development.

[36]  M. Akam,et al.  The molecular basis for metameric pattern in the Drosophila embryo. , 1987, Development.

[37]  W. K. Metcalfe,et al.  Segmental homologies among reticulospinal neurons in the hindbrain of the zebrafish larva , 1986, The Journal of comparative neurology.

[38]  B. Mendelson.  Development of reticulospinal neurons of the zebrafish. I. Time of origin , 1986, The Journal of comparative neurology.

[39]  W. K. Metcalfe,et al.  T reticular interneurons: A class of serially repeating cells in the zebrafish hindbrain , 1985, The Journal of comparative neurology.

[40]  W. K. Metcalfe,et al.  Brain neurons which project to the spinal cord in young larvae of the zebrafish , 1982, The Journal of comparative neurology.

[41]  G. Streisinger,et al.  Production of clones of homozygous diploid zebra fish (Brachydanio rerio) , 1981, Nature.

[42]  C. Nüsslein-Volhard,et al.  Mutations affecting segment number and polarity in Drosophila , 1980, Nature.

[43]  C. Kimmel,et al.  Radiosensitivity and time of origin of Mauthner neuron in the zebra fish. , 1978, Developmental biology.

[44]  S. Vaage.  The segmentation of the primitive neural tube in chick embryos (Gallus domesticus). A morphological, histochemical and autoradiographical investigation. , 1969, Ergebnisse der Anatomie und Entwicklungsgeschichte.

[45]  M. Deol.  THE ABNORMALITIES OF THE INNER EAR IN KREISLER MICE. , 1964, Journal of embryology and experimental morphology.