QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Gomes, J.-E. Articles by Bowerman, B. Search for Related Content PubMed PubMed Citation Articles by Gomes, J.-E. Articles by Bowerman, B.

The maternal gene spn-4 encodes a predicted RRM protein required for mitotic spindle orientation and cell fate patterning in early C. elegans embryos

José-Eduardo Gomes, Sandra E. Encalada, Kathryn A. Swan^*, Christopher A. Shelton, J. Clayton Carter and Bruce Bowerman

Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
^* Present address: Genomics, Exelixis Inc., San Francisco, CA, 94083, USA
Present address: Dept. of Comparative Genetics, GlaxoSmithKline, King of Prussia, PA 19406, USA

Author for correspondence (e-mail: bbowerman{at}molbio.uoregon.edu)

Accepted July 30, 2001

C. elegans embryogenesis begins with a stereotyped sequence of asymmetric cell divisions that are largely responsible for establishing the nematode body plan. These early asymmetries are specified after fertilization by the widely conserved, cortically enriched PAR and PKC-3 proteins, which include three kinases and two PDZ domain proteins. During asymmetric cell divisions in the early embryo, centrosome pairs initially are positioned on transverse axes but then rotate to align with the anteroposterior embryonic axis. We show that rotation of the centrosomal/nuclear complex in an embryonic cell called P₁ requires a maternally expressed gene we name spn-4. The predicted SPN-4 protein contains a single RNA recognition motif (RRM), and belongs to a small subfamily of RRM proteins that includes one Drosophila and two human family members. Remarkably, in mutant embryos lacking spn-4 function the transversely oriented ‘P₁’ mitotic spindle appears to re-specify the axis of cell polarity, and the division remains asymmetric. spn-4 also is required for other developmental processes, including the specification of mesendoderm, the restriction of mesectoderm fate to P₁ descendants, and germline quiescence during embryogenesis. We suggest that SPN-4 post-transcriptionally regulates the expression of multiple developmental regulators. Such SPN-4 targets might then act more specifically to generate a subset of the anterior-posterior asymmetries initially specified after fertilization by the more generally required PAR and PKC-3 proteins.

Key words: Asymmetric cell division, Cell polarity, Centrosome position, Mesectoderm, Mesendoderm, Microtubules, PAR proteins

This article has been cited by other articles:

				S. Jadhav, M. Rana, and K. Subramaniam Multiple maternal proteins coordinate to restrict the translation of C. elegans nanos-2 to primordial germ cells Development, May 15, 2008; 135(10): 1803 - 1812. [Abstract] [Full Text] [PDF]

				D. Mootz, D. M. Ho, and C. P. Hunter The STAR/Maxi-KH domain protein GLD-1 mediates a developmental switch in the translational control of C. elegans PAL-1 Development, July 15, 2004; 131(14): 3263 - 3272. [Abstract] [Full Text] [PDF]

				K.-i. Ogura, N. Kishimoto, S. Mitani, K. Gengyo-Ando, and Y. Kohara Translational control of maternal glp-1 mRNA by POS-1 and its interacting protein SPN-4 in Caenorhabditis elegans Development, June 1, 2003; 130(11): 2495 - 2503. [Abstract] [Full Text] [PDF]

				N. N. Huang, D. E. Mootz, A. J. M. Walhout, M. Vidal, and C. P. Hunter MEX-3 interacting proteins link cell polarity to asymmetric gene expression in Caenorhabditis elegans Development, January 2, 2002; 129(3): 747 - 759. [Abstract] [Full Text] [PDF]