Résumé
The zinc finger motifs (Cys2His2) are found in several proteins playing a role in the regulation of transcripton. SmZF1, a Schistosoma mansoni gene encoding a zinc finger protein was initially isolated from an adult worm cDNA library, as a partial cDNA. The full sequence of the gene was obtained by subcloning and sequencing cDNA and genomic fragments. The collated gene sequence is 2181 nt and the complete cDNA sequence is 705 bp containing the full open reading frame of the gene. Analysis of the genome sequence revealed the presence of three introns interrupting the coding region. The open reading frame theoretically encodes a protein of 164 amino acids, with a calculated molecular mass of 18,667Da. The predicted protein contains three zinc finger motifs, usually present in transcription regulatory proteins. PCR amplification with specific primers for the gene allowed for the detection of the target in egg, cercariae, schistosomulum and adult worm cDNA libraries indicating the expression of the mRNA in these life cycle stages of S. mansoni. This pattern of expression suggests the gene plays a role in vital functions of different life cycle stages of the parasite. Future research will be directed to elucidate the functional role of SmZF1
Sujets)
Animaux , Clonage moléculaire , Gènes d'helminthe/génétique , Protéines d'helminthes/génétique , Schistosoma mansoni/génétique , Doigts de zinc/génétique , Séquence nucléotidique , ADN complémentaire , Protéines de liaison à l'ADN , Amplification de gène , Régulation de l'expression des gènes bactériens , Banque de gènes , Gènes d'helminthe/physiologie , Génome bactérien , Réaction de polymérisation en chaîneRésumé
Sm15 and Sm13 are recognized by antibodies from mice protectely vaccinated with tegumental membranes, suggesting a potencial role in protective immunity. In order to raise antibodies for immunochemical investigations, the genes for these antigens were expressed in pGEX and pMAL vectors so that comparisons could be made among different expression systems and different genes. The fusion proteins corresponding to several parts of the gene for the precursor of Sm15 failed in producing antibodies recognizing the parasite counterpart. On the other hand, antibodies raised against Sm13 MBP-fusion proteins recognized the 13 kDa tegumental protein. Thus the peculiarities of the gene of interest are important and the choice of the expression system must sometimes be decided on an impirical basis.