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

First published online 5 October 2005
doi: 10.1242/dev.02049

This Article Figures Only Full Text Full Text (PDF) All Versions of this Article: dev.02049v1 132/21/4731    most recent 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 Nakamura, Y. Articles by Nishida, H. Search for Related Content PubMed PubMed Citation Articles by Nakamura, Y. Articles by Nishida, H. Social Bookmarking                         What's this?

POPK-1/Sad-1 kinase is required for the proper translocation of maternal mRNAs and putative germ plasm at the posterior pole of the ascidian embryo

¹ Department of Biological Sciences, Graduate School of Science, Osaka University, Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
² Department of Biological Sciences, Tokyo Institute of Technology, Nagatsuda, Midori-ku, Yokohama 226-8501, Japan
³ Faculty of Integrated Arts and Sciences, Tokushima University, 1-1 Minami-Josanjima, Tokushima 770-8502, Japan

^* Author for correspondence (e-mail: yorinaka{at}bio.sci.osaka-u.ac.jp)

Accepted 19 August 2005

Maternal mRNAs localized to specific regions in eggs play important roles in the establishment of embryonic axes and germ layers in various species. Type I postplasmic/PEM mRNAs, which are localized to the posterior-vegetal cortex (PVC) of fertilized ascidian eggs, such as the muscle determinant macho-1 mRNA, play key roles in embryonic development. In the present study, we analyzed the function of the postplasmic/PEM RNA Hr-POPK-1, which encodes a kinase of Halocynthia roretzi. When the function of POPK-1 was suppressed by morpholino antisense oligonucleotides, the resulting malformed larvae did not form muscle or mesenchyme, as in macho-1-deficient embryos. Epistatic analysis indicated that POPK-1 acts upstream of macho-1. When POPK-1 was knocked down, localization of every Type I postplasmic/PEM mRNA examined, including macho-1, was perturbed, showing diffuse early distribution and eventual concentration into a smaller area. This is the probable reason for the macho-1 dysfunction. The postplasmic/PEM mRNAs such as macho-1 and Hr-PEM1 are co-localized with the cortical endoplasmic reticulum (cER) and move with it after fertilization. Eventually they become highly concentrated into a subcellular structure, the centrosome-attracting body (CAB), at the posterior pole of the cleaving embryos. The suppression of POPK-1 function reduced the size of the domain of concentrated cER at the posterior pole, indicating that POPK-1 is involved in the movement of postplasmic/PEM RNAs via relocalization of cER. The CAB also shrank. These results suggest that Hr-POPK-1 plays roles in concentration and positioning of the cER, as well as in the concentration of CAB materials, such as putative germ plasm, in the posterior blastomeres.

Key words: Ascidian embryo, Halocynthia roretzi, RNA localization, postplasmic/PEM RNA, Cortical endoplasmic reticulum, Germ plasm, POPK-1 kinase, Sad-1 kinase

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				W. Hung, C. Hwang, M. D. Po, and M. Zhen Neuronal polarity is regulated by a direct interaction between a scaffolding protein, Neurabin, and a presynaptic SAD-1 kinase in Caenorhabditis elegans Development, January 15, 2007; 134(2): 237 - 249. [Abstract] [Full Text] [PDF]

				M. Shirae-Kurabayashi, T. Nishikata, K. Takamura, K. J. Tanaka, C. Nakamoto, and A. Nakamura Dynamic redistribution of vasa homolog and exclusion of somatic cell determinants during germ cell specification in Ciona intestinalis. Development, July 1, 2006; 133(14): 2683 - 2693. [Abstract] [Full Text] [PDF]

				S. Patalano, G. Pruliere, F. Prodon, A. Paix, P. Dru, C. Sardet, and J. Chenevert The aPKC-PAR-6-PAR-3 cell polarity complex localizes to the centrosome attracting body, a macroscopic cortical structure responsible for asymmetric divisions in the early ascidian embryo J. Cell Sci., April 15, 2006; 119(8): 1592 - 1603. [Abstract] [Full Text] [PDF]