Molecular analysis of spinocerebellar ataxia trinucleotide repeat behavior in normal individuals of a Brazilian population.

There is a current lack of molecular studies analyzing the behavior of trinucleotide repeat expansions causative of Late Onset Spinocerebellar Ataxias in the Brazilian population. Therefore, this manuscript analyses normal families, as well as one hundred normal individuals of the Espirito Santo State to determine the trinucleotide repeat behavior and the allelic frequencies found in this population. The analysis of normal families demonstrated that, instead of being always stably transmitted over generations, expansions can occur between two generations of unaffected individuals, possibly contributing for the appearance of the ataxic phenotype. Allelic frequency studies demonstrated that some alleles are prevalent in the population, namely, allele 32 for the ATXN1 locus (21.5%); allele 21 for the ATXN2 locus (50%); allele 21 and 23 for the ATXN3 locus (14% each); allele 12 for the ATXN6 locus (21%) and allele 10 for the ATXN7 locus (22.5%).

Oncogene-induced transcriptional patterns in established cell lines as a model for in vitro analysis of tumor biology.

Established cell lines have long been used for in vitro studies of tumor biology, enabling investigators to control growth conditions and to draw important conclusions about the oncogenic microenvironment. However, gene expression behavior in cultured cells may not always reflect the actual in vivo scenario, and analysis derived from such experiments should take into consideration the existing differences between the two environments. We used suppression subtractive hybridization to study transcriptional changes elicited after oncogene transformation and cell line establishment. We found that transcriptional changes elicited in cultured cell lines are in fact representative of late events, and they do not occur early after oncogene transfection or activation. We also determined that a fraction of the transcriptional changes is oncogene specific, whereas other changes are shared between two or more different oncogenes.