PAR-3 is required for epithelial cell polarity in the distal spermatheca of C. elegans.

Shinya Aono,Renaud Legouis,Kenneth J Kemphues,Wendy A Hoose

doi:10.1242/dev.01146

Abstract

PAR-3 is localized asymmetrically in epithelial cells in a variety of animals from Caenorhabditis elegans to mammals. Although C. elegans PAR-3 is known to act in early blastomeres to polarize the embryo, a role for PAR-3 in epithelial cells of C. elegans has not been established. Using RNA interference to deplete PAR-3 in developing larvae, we discovered a requirement for PAR-3 in spermathecal development. Spermathecal precursor cells are born during larval development and differentiate into an epithelium that forms a tube for the storage of sperm. Eggs must enter the spermatheca to complete ovulation. PAR-3-depleted worms exhibit defects in ovulation. Consistent with this phenotype, PAR-3 is transiently expressed and localized asymmetrically in the developing somatic gonad, including the spermathecal precursor cells of L4 larvae. We found that the defect in ovulation can be partially suppressed by a mutation in IPP-5, an inositol polyphosphate 5-phosphatase, indicating that one effect of PAR-3 depletion is disruption of signaling between oocyte and spermatheca. Microscopy revealed that the distribution of AJM-1, an apical junction marker, and apical microfilaments are severely affected in the distal spermatheca of PAR-3-depleted worms. We propose that PAR-3 activity is required for the proper polarization of spermathecal cells and that defective ovulation results from defective distal spermathecal development.

Highlights

Acquisition of cell polarity is important to epithelial cells for carrying out their barrier function and for their proper movements during morphogenesis (Knust and Bossinger, 2002; Ohno, 2001)
The control plate had >500 embryos, whereas the par3(RNAi) plate had only 70. These results suggest that PAR-3 depletion affects oogenesis or ovulation
In order to clarify the basis for the defects in organization and function of the distal spermatheca, we examined the distribution of three proteins with polarized accumulation in epithelial cells: AJM-1, LET-413 and actin

Summary

Introduction

Acquisition of cell polarity is important to epithelial cells for carrying out their barrier function and for their proper movements during morphogenesis (Knust and Bossinger, 2002; Ohno, 2001). From genetic studies on Drosophila embryonic ectoderm, C. elegans gut epithelium and mammalian culture cells, it appears that three independent protein-complexes accumulating along the plasma membrane are required for regulating the formation of this specialized junctional structure: the PAR-3/PAR-6/aPKC complex, the Scribble/Dlg/Lgl complex, and the Crumbs/ Stardust complex (Betschinger et al, 2003; Bilder et al, 2003; Hurd et al, 2003; Johnson and Wodarz, 2003; Knust and Bossinger, 2002; Plant et al, 2003; Tanentzapf and Tepass, 2003; Yamanaka et al, 2003) One of these complexes, the PAR-3/PAR-6/aPKC complex, plays a fundamental role in establishing cell polarities essential for asymmetric divisions in the early embryo in C. elegans (for reviews, see Kemphues and Strome, 1997; Pellettieri and Seydoux, 2002), but to date there has been no evidence for a role in epithelial polarity in this animal. To explore a possible role for PAR-3 in vulval development, we depleted PAR-3 post-embryonically using RNAi

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Conclusion