Gene activity in the salivary gland of Bradysia hygida (Diptera, Sciaridae): a) the activity control of gene bhsgamp-1; b) the effect of 5-bromodeoxyuridine on the amplified gene activity; c) searching for amplified genes of the second group

• Grant number: 09/53965-8
• Support Opportunities: Regular Research Grants
• Start date: June 01, 2010
• End date: November 30, 2012
• Field of knowledge: Biological Sciences - Morphology - Cytology and Cell Biology
• Principal Investigator: Jorge Cury de Almeida
• Grantee: Jorge Cury de Almeida
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

A) We have found a reiterated gene, developmentally regulated, that encodes an antimicrobial peptide and is exclusively expressed in the salivary gland. The peptide is secreted into the saliva, during the larval and larval/pupal molts. The hormone 20-OH ecdysone (20E) plays a direct role in the gene regulation. We are interested in to understand the particularities of this control. Our hypothesis is that this gene is part of a preventive system of defense that intends to protect the larvae during the tegument changes, killing the pathogenic microorganisms, in the immediate vicinity of the animals. We want to express the peptide in heterologous system, and test its action against microorganisms that are pathogenic to humans. B) We demonstrated that 5-BrdUrd has na impressing morphological effect on the DNA puffs. The chromatin of these sites remains strongly compacted, after incorporating the analogue. The DNA puffs do not expand. We are studing this morphological effect on the activity of especific amplified genes, situated in some of these puffs. C) Two groups of amplified genes are present in two distinct groups of DNA puffs. The activity of the first group demands high concentrations of 20E; the second group of genes only are activated in the presence of low levels of the hormone. Some genes of the first group were already cloned and are being studied. From the second group, any gene was characterized. We are trying to produce cDNA, using poly (A+)RNA from salivary glands, in which the second group of amplilfied genes is active, to select and characterize complementary fragments to some of these genes. (AU)