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Proteolytic activity of <i>Boophilus microplus</i> Yolk pro-Cathepsin D (BYC) is coincident with cortical acidification during embryogenesis

Abreu, LA Valle, D Manso, PPA Façanha, AR Pelajo-Machado, M Masuda, H Masuda, A Vaz, I Lenzi, H Oliveira, PL Logullo, C

Univ Estadual N Fluminen CBB Lab Quim & Funcao Prot & Pepideos BR-28015620 Campos dos Goytacazes RJ BrazilUniv Fed Rio de Janeiro CCS ICB Dept Bioquim Med BR-21941690 Rio de Janeiro BrazilUniv Fed Rio Grande do Sul Ctr Biotecnol BR-91501970 Porto Alegre RS BrazilUniv Fed Rio Grande do Sul Fac Vet BR-91501970 Porto Alegre RS BrazilIBEx Entomol Lab BR-20911270 Rio De Janeiro BrazilFiocruz MS Dept Entomol Inst Oswaldo Cruz Lab Transmissores Hematozoarios BR-21045900 Rio De Janeiro BrazilFiocruz MS Inst Oswaldo Cruz Dept Patol BR-21045900 Rio De Janeiro Brazil

来源详细信息

关键词： tick Boophilus microplus proteinase embryogenesis yolk protein acidification

摘要： In a previous report (Parasitology 116 (1998) 525) we isolated and characterized Boophilus Yolk pro-Cathepsin (BYC), an aspartic proteinase precursor from the eggs of the hard tick. The present study was designed to characterize the function of BYC in the consumption of vitellin (VT), the major yolk protein, during embryogenesis. Both purified BYC and total egg homogenate proteolytic activity showed a similar pH dependence profile with an acidic optimum. Purified BYC presented higher activity against VT as a substrate when compared to other proteins. The VT degradation pattern observed in vitro also showed a similar profile to that observed in vivo. Co-localization of BYC and acidic cortical yolk granules was performed by immunocytochemistry and confocal microscopy. Proton-pumping activity of yolk granules in vitro was higher in eggs collected 4 day after oviposition than in newly laid eggs. Taken together, our data suggest that BYC plays a major role in the degradation of VT and that its activity is controlled by acidification of yolk platelets localized at the cortical cytoplasm of the developing Boophilus microplus egg. (C) 2004 Elsevier Ltd. All rights reserved.

Role of the ERK-mediated signaling pathway in mesenchyme formation and differentiation in the sea urchin embryo

Fernandez-Serra, M Consales, C Livigni, A Arnone, MI

Staz Zool Anton Dohrn I-80121 Naples Italy

来源 PubMed

MEDLINE期刊

详细信息

关键词： MAP kinase ERK MEK ets erg epithelial-mesenchyme transition sea urchin embryo

摘要： Mesoderm and mesodermal structures in the sea urchin embryo are entirely generated by two embryologically distinct populations of mesenchyme cells: the primary (PMC) and the secondary (SMC) mesenchyme cells. We have identified the extracellular signal-regulated kinase (ERK) as a key component of the regulatory machinery that controls the formation of both these cell types. ERK is activated in a spatial-temporal manner, which coincides with the epithelial-mesenchyme transition (EMT) of the prospective PMCs and SMCs. Here, we show that ERK controls EMT of both primary and secondary mesenchyme cells. Loss and gain of function experiments demonstrate that ERK signaling is not required for the early specification of either PMCs or SMCs, but controls the maintenance and/or the enhancement of expression levels of regulatory genes which participate in the process of specification of these cell types. In addition, ERK-mediated signaling is essential for the transcription of terminal differentiation genes encoding proteins that define the final structures generated by PMCs and SMCs. Our findings suggest that ERK has a central pan-mesodermal role in coupling EMT and terminal differentiation of all mesenchymal cell types in the sea urchin embryo. (C) 2004 Elsevier Inc. All rights reserved.

美科学家首次利用冷冻人类卵巢组织培育出胚胎

新华社

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