Protein interactions with a gender-specific gene of Schistosoma mansoni: characterization by DNase I footprinting, band shift and UV cross-linking.

A schistosome gender specific gene (F-10), was used as a probe to characterize DNA binding proteins from adult male and female Schistoma mansoni. Using the band-shift and DNase I footprinting methods, it was found that proteins from male and female worms bound to the intact F-10 gene and to restriction fragments corresponding to different domains of the gene, generating relatively long protected sites. Clear differences between male and female proteins were only observed when nuclear proteins were tested. Thus, gender-specific binding was detected in fragments corresponding to the 5' and 3' ends. UV-induced cross-linking between schistosome proteins and a synthetic oligonucleotide bearing a steroid response element present in the 3' untranslated end of the F-10 gene, revealed a major DNA binding protein with a molecular mass of 30 kDa, in both male and female worms. These results suggested that the activation of transcription of the F-10 gene may depend essentially on nuclear proteins.