The SOS response of Caulobacter crescentus and the relationship between DNA repair mechanisms and the cell cycle progression.

Author(s)

Raquel Paes da Rocha

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2011-05-17

Examining board members

Carlos Frederico Martins Menck; Regina Lúcia Baldini; Suely Lopes Gomes; Frederico José Gueiros Filho; Paulo Lee Ho

• Advisor: Carlos Frederico Martins Menck

Abstract

Caulobacter crescentus belongs to the proteobacteria group and exhibts the distinctive feature of cellular differentiation after each division. This work aimed to reveal the DNA repair mechanisms in C. crescentus. We have identified 44 genes belonging to the SOS regulon through the construction of a mutant strain to its repressor. We have functionally characterized some of its genes, like CC_2272 (that encodes an endonuclease III family protein) and CC_2433. The lexA strain showed filamentous morphology, e because of that, we have tried to discover which the genetic factors responsible for this morphology were. We have also investigated the cell cycle control processes after the introduction of damages in the DNA by the UVC light, in mutant strains deficient in different repair pathways. These experiments showed us that prokaryotic cells possess mechanisms to couple the cell cycle progression to the integrity of the genetic material. This work opens new and exciting possibilities in the field of bacterial biology. (AU)