Identification DNA repair related genes in Caulobacter crescentus through the identification of mutations affecting sensitivity to genotoxic agents.

Author(s)

Regina Célia Pereira Marques

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2008-06-27

Examining board members

Carlos Frederico Martins Menck; Regina Lúcia Baldini; Rita de Cassia Cafe Ferreira; Valeria Cristina da Silva Italiani; Lucymara Fassarela Agnez Lima

• Advisor: Carlos Frederico Martins Menck

Abstract

This work aimed to identify genes related to DNA damage protection in C. crescentus, by means of screening a Tn5 -mutated library for clones sensitive to UV-B light and MMS. Out of 249 selected clones, we were able to identify mutations in 102 genes, classified in ten different functional categories, including DNA metabolism. In addition to genes already described as playing a role in genome defense to lesions, the results provide new potential functions to several other genes. More detailed investigation indicates also that the mutations in some of these genes may also affect cell stress and cell cycle, being potentially involved in check-point responses. Moreover, mutants for nucleotide excision repair genes were also found to be sensitive to H2O2, indicating that this DNA repair system also acts in DNA oxidative damage. These data are the first establishing a role in genome protection for several genes in C. crescentus, as well as other alpha-proteobacteria. (AU)