Search for genes related to the mutator phenotypes in Caulobacter crescentus.

Author(s)

Marinalva Martins Pinheiro

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2007-10-17

Examining board members

Carlos Frederico Martins Menck; Mário Henrique de Barros; Carla Columbano de Oliveira; Mariana Cabral de Oliveira; Ana Clara Guerrini Schenberg

• Advisor: Carlos Frederico Martins Menck

Abstract

The \"in silico\" comparison of the main DNA repair genes between C. crescentus and E. coli shows significant differences between these bacteria, suggesting biological diversity in bacterial responses to DNA damage. We further screened a C. crescentus library of 5,000 clones mutated by random insertion of the TN5 transposon in the genome, searching for clones with high levels of spontaneous rifampicin resistance mutations. Most of the genes identified have not been previously reported as related to mutator phenotype, but, as expected, we have also identified proteins already known as causing mutator phenotypes when mutated. As part of the functional characterization, some candidate clones were characterized based on rpoB gene sequences aiming at indicating the mutational process under specific genetic background conditions. Analysis of some candidate clones based on measurements of promoter activity with lacZ transcriptional fusions show that the system SOS is modified in some clones and this justify part of their mutator phenotype. (AU)