The A subunit of NF-Y nuclear factor from Schistosoma mansoni was expr
essed in E. coli fused to a histidine tag and purified by affinity chr
omatography using a Ni2+-Agarose matrix. Antibodies against the recomb
inant protein were prepared and used for Western blot and immunolocali
zation. The presence of SMNF-YA in all stages of the parasite life-cyc
le was determined by RT-PCR and Western blot analysis. The immunolocal
ization of SMNF-YA showed the presence of this factor in a parenchymal
cell population of cercariae and adult worms and in embryos within eg
gs. The expression of SMNF-YA was demonstrated to decrease in maturati
ng spermatozoites whereas an accumulation of this factor was observed
in the nucleus from oocytes during their maturation processes.