In our first renewal application (funded from May 1,1998-April 30, 2002), we proposed to examine the role of Wnt signaling during endoderm induction in C. elegans. We have since shown that a conserved MAP Kinase module converges with Wnt signaling to polarize endoderm potential within a single embryonic cell called EMS. We also showed that Wnt signaling induces a rotation of the mitotic spindle in EMS, such that its posterior daughter inherits endoderm potential. Our findings provide important mechanistic insights about a key signal transduction pathway that is widely conserved, being involved in several important human cancers and in many different developmental processes. Four other cell divisions in the early embryo are intrinsically asymmetric. In each case, as in EMS, the mitotic spindle rotates to align with the axis of polarization. We have identified new mutants with mitotic spindle positioning defects in two intrinsically polarized embryonic cells called P0 and P1. We propose new specific aims that focus largely on intrinsic polarity in these two cells. We are investigating a gene we discovered called spn-4, which encodes a conserved RNA binding protein that acts downstream of the PAR polarity proteins to regulate mitotic spindle orientation and cell polarity in P1. We also proposed to study another mutant we recently identified, called spn-5, that exhibits P1 spindle orientation defects, and four new mutants (spn-6-9) with defects in P0 mitotic spindle positioning. Finally, we propose a novel and powerful screen to identify genes required for spindle orientation and asymmetric cell division. We are using RNA interference to identify loci throughout the genome that, when reduced in function, can enhance or suppress conditional mutants grown at just-viable or just-lethal temperatures. Our long-term goal is to attain a comprehensive view of the pathways that regulate cell polarity in the early C. elegans embryo.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM049869-10
Application #
6618577
Study Section
Cell Development and Function Integrated Review Group (CDF)
Program Officer
Greenberg, Judith H
Project Start
1994-05-01
Project End
2007-04-30
Budget Start
2003-05-01
Budget End
2004-04-30
Support Year
10
Fiscal Year
2003
Total Cost
$286,195
Indirect Cost
Name
University of Oregon
Department
Biochemistry
Type
Organized Research Units
DUNS #
948117312
City
Eugene
State
OR
Country
United States
Zip Code
97403
Sugioka, Kenji; Fielmich, Lars-Eric; Mizumoto, Kota et al. (2018) Tumor suppressor APC is an attenuator of spindle-pulling forces during C. elegans asymmetric cell division. Proc Natl Acad Sci U S A 115:E954-E963
Sugioka, Kenji; Bowerman, Bruce (2018) Combinatorial Contact Cues Specify Cell Division Orientation by Directing Cortical Myosin Flows. Dev Cell 46:257-270.e5
Mok, Calvin A; Au, Vinci; Thompson, Owen A et al. (2017) MIP-MAP: High-Throughput Mapping of Caenorhabditis elegans Temperature-Sensitive Mutants via Molecular Inversion Probes. Genetics 207:447-463
Sugioka, Kenji; Hamill, Danielle R; Lowry, Joshua B et al. (2017) Centriolar SAS-7 acts upstream of SPD-2 to regulate centriole assembly and pericentriolar material formation. Elife 6:
Severson, Aaron F; von Dassow, George; Bowerman, Bruce (2016) Oocyte Meiotic Spindle Assembly and Function. Curr Top Dev Biol 116:65-98
Lowry, Josh; Yochem, John; Chuang, Chien-Hui et al. (2015) High-Throughput Cloning of Temperature-Sensitive Caenorhabditis elegans Mutants with Adult Syncytial Germline Membrane Architecture Defects. G3 (Bethesda) 5:2241-55
Connolly, Amy A; Sugioka, Kenji; Chuang, Chien-Hui et al. (2015) KLP-7 acts through the Ndc80 complex to limit pole number in C. elegans oocyte meiotic spindle assembly. J Cell Biol 210:917-32
Du, Zhuo; He, Fei; Yu, Zidong et al. (2015) E3 ubiquitin ligases promote progression of differentiation during C. elegans embryogenesis. Dev Biol 398:267-79
Phillips, Patrick C; Bowerman, Bruce (2015) Cell biology: scaling and the emergence of evolutionary cell biology. Curr Biol 25:R223-R225
Keikhaee, Mohammad R; Nash, Eric B; O'Rourke, Sean M et al. (2014) A semi-dominant mutation in the general splicing factor SF3a66 causes anterior-posterior axis reversal in one-cell stage C. elegans embryos. PLoS One 9:e106484

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