We propose to identify and characterize genes required for vertebrate somitogenesis, the process by which a 'homogeneous' field of pre- somatic cells is divided into reiterated segments called somites. Zebrafish are well suited for this task, as mutational screens can be performed with relative ease. Additionally, wild-type and mutant cells can be studied at single cell resolution, a critical feature if we are to understand how cells on one side of a somite boundary become distinct from their neighbors on the other side, just one cell diameter away. Recently, vertebrate homologs of Drosophila hairy/Enhancer of split [E(sp)] genes (her or hes genes) have been described that are expressed in wave-like fashion in the pre-somatic mesoderm, cycling with a periodicity equal to the time it takes to generate a somite. Two of the mutations we have isolated, one deleting her gene function and one causing ectopic her gene expression, will e used to understand the specific role of her genes and to investigate her genes are regulated during somitogenesis. To isolate additional genes, we will continue our sensitive genetic screen to isolate mutations that disrupt the segmental gene expression of her1, a zebrafish hairy/E(sp1)-related gene. Regulatory mechanisms governing segmentation in flies and dish appear distinct, likely reflecting the basic mechanistic differences between segmentation in these diverse organisms. For example, Notch/Delta signaling has been implicated in vertebrate somitogenesis, but is not required for fly segmentation. The experiments proposed will identify molecules involved in cell specification and cell-cell communication and begin to establish a regulatory hierarchy for their action. These studies will highlight molecules of potential importance in human development, as well as generate potential models for human genetic disease. Notch signaling has been implicated in somitogenesis, cell proliferation, cell fate decisions, organ and stem cell differentiation programs, and cancer, although the mechanisms by which notch signalling controls these diverse developmental decisions is largely unknown. The proposed screen will likely isolate mutations in genes already implicated in somite formation, but importantly, its unbiased approach will likely lead to the identification of previously undescribed molecules involved in Notch/Delta signaling, cell specification, and cell-cell communication.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM061952-03
Application #
6708014
Study Section
Genetics Study Section (GEN)
Program Officer
Carter, Anthony D
Project Start
2002-04-01
Project End
2007-03-31
Budget Start
2004-04-01
Budget End
2005-03-31
Support Year
3
Fiscal Year
2004
Total Cost
$210,256
Indirect Cost
Name
University of California Berkeley
Department
Biochemistry
Type
Schools of Arts and Sciences
DUNS #
124726725
City
Berkeley
State
CA
Country
United States
Zip Code
94704
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Morrow, Zachary T; Maxwell, Adrienne M; Hoshijima, Kazuyuki et al. (2017) tbx6l and tbx16 are redundantly required for posterior paraxial mesoderm formation during zebrafish embryogenesis. Dev Dyn 246:759-769
Shih, Nathan P; François, Paul; Delaune, Emilie A et al. (2015) Dynamics of the slowing segmentation clock reveal alternating two-segment periodicity. Development 142:1785-93
Beahm, Brendan J; Dehnert, Karen W; Derr, Nicolas L et al. (2014) A visualizable chain-terminating inhibitor of glycosaminoglycan biosynthesis in developing zebrafish. Angew Chem Int Ed Engl 53:3347-52
Delaune, Emilie A; Francois, Paul; Shih, Nathan P et al. (2012) Single-cell-resolution imaging of the impact of Notch signaling and mitosis on segmentation clock dynamics. Dev Cell 23:995-1005
Fior, Rita; Maxwell, Adrienne A; Ma, Taylur P et al. (2012) The differentiation and movement of presomitic mesoderm progenitor cells are controlled by Mesogenin 1. Development 139:4656-65
Parra, Marilyn K; Gallagher, Thomas L; Amacher, Sharon L et al. (2012) Deep intron elements mediate nested splicing events at consecutive AG dinucleotides to regulate alternative 3' splice site choice in vertebrate 4.1 genes. Mol Cell Biol 32:2044-53
Dehnert, Karen W; Baskin, Jeremy M; Laughlin, Scott T et al. (2012) Imaging the sialome during zebrafish development with copper-free click chemistry. Chembiochem 13:353-7
Gallagher, Thomas L; Arribere, Joshua A; Geurts, Paul A et al. (2011) Rbfox-regulated alternative splicing is critical for zebrafish cardiac and skeletal muscle functions. Dev Biol 359:251-61
Dehnert, Karen W; Beahm, Brendan J; Huynh, Thinh T et al. (2011) Metabolic labeling of fucosylated glycans in developing zebrafish. ACS Chem Biol 6:547-52

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