Chitin-binding proteins of Artemia diapause cysts participate in formation of the embryonic cuticle layer of cyst shells.
Biochem J
; 449(1): 285-94, 2013 Jan 01.
Article
em En
| MEDLINE
| ID: mdl-23013449
ABSTRACT
The brine shrimp Artemia reproduces either ovoviviparously, producing free-swimming nauplii, or oviparously, producing encysted embryos (diapause cysts) able to cope with harsh and complex habitats. When the cysts enter diapause they are encased in a complex external shell that protects them from certain extreme environments. The genomic comparison of oviparous and ovoviviparous ovisacs has been described previously. We isolated three significantly up-regulated genes in oviparous oocytes and identified them as Arp-CBP (Artemia parthenogenetica chitin-binding protein) genes. Quantitative real-time PCR indicated that the expression of Arp-CBP genes gradually increases during diapause cyst formation and significant mRNA accumulation occurs during the ovisac stage of oviparous development. Moreover, in situ hybridization results demonstrated that Arp-CBP mRNAs are expressed in the embryo. Interestingly, the results of immune electron microscopy showed that all three Arp-CBPs are distributed throughout the cellular ECL (embryonic cuticle layer) of the cyst shell. Furthermore, knockdown of Arp-CBP by RNA interference resulted in marked changes in the composition of the embryonic cuticular layer. The fibrous layer of the cyst shell adopted a loose conformation and the inner and outer cuticular membranes exhibited marked irregularities when Arp-CBP expression was suppressed. Finally, an in vitro recombinant protein-binding assay showed that all three Arp-CBPs have carbohydrate-binding activities. These findings provide significant insight into the mechanisms by which the ECL of Artemia cyst shell is formed, and demonstrate that Arp-CBPs are involved in construction of the fibrous lattice and are required for formation of the ECL of the cyst shell.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Artemia
/
Proteínas de Transporte
/
Quitina
/
Embrião não Mamífero
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
Biochem J
Ano de publicação:
2013
Tipo de documento:
Article