PROTEIN-DNA ASSOCIATIONS IN A GENDER-SPECIFIC GENE OF SCHISTOSOMA-MANSONI - CHARACTERIZATION BY UV CROSS-LINKING, DNASE-I FOOTPRINTING AND BAND SHIFT ASSAYS

Protein extracts obtained from male and female schistosomes were incub ated with a gender-specific gene, F-10, transcribed only in adult fema les and encoding a major egg-shell protein. The protein/DNA interactio n was measured using the band shift, DNase-I-footprinting and UV cross -linking techniques. The results showed a clear band shift when a 302 bp restriction fragment containing the 3' end of the gene was incubate d with either female or male proteins. This fragment also contained a putative steroid hormone regulatory element (HRE). In contrast, only t he male proteins produced a shift with the 495 bp fragment correspondi ng to the middle region of the gene. DNase I footprinting showed that proteins from males and females interacted with the F-10 gene by bindi ng to multiple adjacent sites along the DNA, thus generating relativel y long protected fragments of approximately 100 bp. This result sugges ted that the adjacent binding of several moles of protein occurred at the 5' end of the gene. UV cross-linking between schistosome proteins and a 21 bp synthetic oligonucleotide containing the F-10 HRE, evidenc ed proteins having MWS of 30,45 and 65 kDa. These proteins are presuma bly involved in the regulation of transcription of the F-10 gene.