The genes Encoding Glutathione S-transferases in the Honeybee (Apis mellifera): expression, regulation and function during and After Metamorphosis.

Author(s)

Guaracini Aparecida Loterio

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC)
• Defense date: 2011-10-27

Examining board members

Marcia Maria Gentile Bitondi; Maria Cristina Arias; Klaus Hartmann Hartfelder

• Advisor: Marcia Maria Gentile Bitondi

Abstract

In insects, the enzymes glutathione S-transferases (GSTs) are known for their ability to degrade insecticides, pesticides and other chemical compounds, natural or not, which are not normally produced or expected to be present in the organism. GSTs can also promote the intracellular transportation of hormones and metabolites as well as act in the cellular protection against oxidative stress. In addition, the GST function has been associated with the process of sequestration, by the fat body, of one type of protein (hexamerin) which is stored in the larval hemolymph to be used as a source of amino acids during metamorphosis. The aims of this study were (1) to characterize structure and expression, and explore the roles of the GST encoding genes in Apis mellifera worker bees and, (2) to investigate the potential role of one of these genes, hp191(GSTS1), in the dynamics of hexamerin sequestration during metamorphosis. The methodology included molecular biology techniques, such as semiquantitative and real time RT-PCR, gene sequencing and silencing, and western blot. Briefly, the results revealed structural differences (number and organization of introns and exons) among the ten GSTs genes of A. mellifera, increased activity of these genes associated to bee aging and the intense foraging activity, and modulation of the expression levels of GST genes by the type of diet. The results also revealed that the expression profile of hp191(GSTS1), as well as its response to the morphogenetic hormones (juvenile hormone and 20-hydroxyecdysone), are consistent with a function in metamorphosis. Furthermore, hp191(GSTS1) silencing mediated by RNAi resulted in decreased hemolymph levels of a hexamerin (HEX 70a) with an essential function in metamorphosis. Altogether, these data provide novel findings concerning the structure, expression and function of the GSTs genes of A. mellifera with a special focus on the potential participation of hp191(GSTS1) in metamorphosis. (AU)

• FAPESP's process: 10/04371-5 - hp19 gene: expression, regulation and function in the metamorphosis of Apis mellifera
• Grantee: Guaracini Aparecida Loterio
• Support Opportunities: Scholarships in Brazil - Master