RESUMO
We have studied the gene expression, especially of the oncoproteins, and its regulation in schistosomes. Schistosomes have a complex life cycle with defined dimorphic lifestyle. The parasite are so far unique in biology in expressing oncogene products in their adult stage. In order to characterize the expression and developmental regulation, a lambda gt 11 cDNA library and lambda EMBL4 genomic DNA library of each growth stage of Schistosoma mansoni and S. japonicum was constructed, and was screened with various monoclonal antibodies against ongogene products. One positive plaque reacted to anti-p53 antibody (Ab-2, Oncogene Science, Inc.) was further analyzed. This fusion protein was about 120 KDa in molecular weights, and expressed as 1.4 Kb RNA in the adult stage. P53 gene is well-known as the negative regulator of the cell cicle, and the mutations in the gene are turning out to be the most common genetic alterations in human cancers. The comparison of the gene structure among species and stages were being conducted. Chromosome structures, C-band formation, and the results of in situ hybridization using the phage probe would be discussed
Assuntos
Proteínas Oncogênicas Virais/genética , Schistosoma/genéticaRESUMO
Chromosome observations of triatomine bugs known as medically important vectors of American tripanosomiasis (Chagas' disease) were attempted. We demonstrated by the C-band technique that brazilian strain of Triatoma infestans includes at least three cytotypes in terms of constitutive heterochromatin polymorphism. We found cytological evidence that there is a significant difference in cytotype frequencies betweenobserved values and expected ones from Hardy-Weinberg principle. This evidence suggests a genetic regulation or an incompatibility mechanism between cytotypes, which will serve as hopeful cytological markers for vector control