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ID 32976
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Author
Gusev, Oleg
Ikeda, Hideki
Okochi, Tetsushi
Lee, Jae Min
Hatakeyama, Masatsugu
Kobayashi, Chiyoko
Agata, Kiyokazu
Abstract

The egg attachment system of an estuarine crab Sesarma haematocheir is formed on the maternal ovigerous hairs just after egg laying, and slips off these hairs just after hatching. The stripping is caused by an active factor that we call OHSS (ovigerous-hair stripping substance), which is released by the embryo upon hatching. OHSS was purified, and its active form had a molecular mass of 25·kDa. The cDNA of OHSS cloned from an embryonic cDNA library was 1759·bp long, encoding 492 amino acids in a single open reading frame (ORF). The C-terminal part of the predicted protein was composed of a trypsin-like serine protease domain, with homology to counterparts in other animals of 33–38%. The predicted protein (54.7·kDa) secreted as a zymogen may be cleaved post-translationally, separating the Cterminal from the N-terminal region. The OHSS gene was expressed in the embryo at least 2 weeks before hatching. Expression was also detected in the zoea larva 1 day after hatching and in the brain of the female. However, it was not detected in the muscle, hepatopancreas or ovigerous seta of the female. Ultrastructural analysis indicated that the material investing maternal ovigerous hair, i.e. the outermost layer (E1) of the egg case, is attached at the special sites (attachment sites) arranged at intervals of 130–160·nm on the hair. It is suggested that OHSS acts specifically at these sites, lysing the bond with the coat, thus disposing of the embryo attachment system. This enables the female to prepare the next clutch of embryos without ecdysis.

Keywords
crab
Sesarma (or Chiromantes) haematocheir
ovigerous hair
embryo attachment system
investment coat
stripping
ovigerous-hair stripping substance (OHSS)
serine protease.
Note
Digital Object Identifer:10.1242/jeb.00785
Published with permission from the copyright holder. This is the institute's copy, as published in The Journal of Experimental Biology, February 2004, Volume 207, Issue 4, Pages 621-632.
Publisher URL:http://dx.doi.org/10.1242/jeb.00785
Direct access to Thomson Web of Science record
Copyright © 2004 The Company of Biologists Ltd. All rights reserved.
Published Date
2004-2
Publication Title
The Journal of Experimental Biology
Volume
volume207
Issue
issue4
Start Page
621
End Page
632
Content Type
Journal Article
language
英語
Refereed
True
DOI
Web of Sience KeyUT
Submission Path
biology_general/11