We have studied the presence of four sperm glycosidases, α-mannosidase, α-L- fucosidase and two β-hexosaminidase isoforms, in 11 species of the genus Drosophila spanning approximately an evolutionary 60 MY period, and in Scaptodrosophila lebanonensis, belonging to the ancestor genus Scaptodrosophila. These enzymes had been previously identified in Drosophila melanogaster as putative receptors for glycoconjugates of the egg surface. Alpha-mannosidase and β-hexosaminidases are intrinsic proteins of the sperm plasma membrane in species closely related to D. melanogaster as well as in the divergent species D. willistoni, D. hydei, D. virilis, and S. lebanonensis. Alpha-L-fucosidase is restricted to the species of the genus Drosophila. Alpha-mannosidase and β-hexosaminidases have been purified and characterized in all species. Their molecular masses and optimal pHs are similar in all the species, whereas interspecific differences in enzyme activities were detected. Cross-species comparison of kinetic parameters indicated a relationship between enzyme efficiency and phylogenetic relatedness. Beta-hexosaminidases were the most efficient enzymes. Lectin cytochemistry suggested the presence of carbohydrate residues complementary to the glycosidases on the eggshell at the site of sperm entry in all species. Bioinformatic analysis of the coding sequences of β-hexosaminases and α-L-fucosidase and of their predicted products showed no evidence of positive selection of the genes coding for these enzymes and a high degree of sequence identity of the predicted polypeptides among the species of the genus Drosophila. Collectively, our findings indicate that the Drosophila sperm glycosidases are structurally and functionally conserved and strengthen the hypothesis of their involvement in the interactions with the egg surface.
Interspecific analysis of the glycosidases of the sperm plasma membrane in Drosophila / J. Intra, F. Cenni, G. Pavesi, M. Pasini, M.E. Perotti. - In: MOLECULAR REPRODUCTION AND DEVELOPMENT. - ISSN 1040-452X. - 76:1(2009 Jan), pp. 85-100.
|Titolo:||Interspecific analysis of the glycosidases of the sperm plasma membrane in Drosophila|
INTRA, JARI (Primo)
PASINI, MARIA ENRICA (Penultimo)
|Parole Chiave:||drosophila spermatozoa; glycosidases; hexosaminidase; fucosidase; mannosidase; fertilization|
|Settore Scientifico Disciplinare:||Settore BIO/06 - Anatomia Comparata e Citologia|
|Data di pubblicazione:||gen-2009|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1002/mrd.20932|
|Appare nelle tipologie:||01 - Articolo su periodico|