Keronninn Moreno de Lima Bessa
From DNA Repair Lab
I undergraduated in Biology at the Federal University of Rio Grande do Norte. In 2006, I got my PhD in Biotechnology at the University of Sao Paulo, Brazil. Nowadays, I am supported by a Postdoctoral Fellowship from FAPESP.
Research projectUltraviolet light (UV) generates DNA lesions, cyclobutante pyrimidine dimers (CPDs) and 6-4 pyrimidine-pyrimidone photoproducts being the most frequent ones. These DNA lesions can be removed from the genome by two different DNA repair processes: photoreactivation and nucleotide excision repair (NER). Photoreactivation involves enzymes named photolyases, which contain chromophores that capture blue photons and use them to repair the UV photoproducts. Interestingly, these enzymes present a high specificity to the target lesion, being classified as CPD-photolyases and 6-4PP-photolyases. Even though photoreactivation has been found widespread in the nature, these enzymes are absent in placental mammals, including humans. In these organisms, repair of UV-induced DNA lesions is performed by NER. Our research work is interested in investigating the effects of CPDs and 6-4PPs on the induction of cellular responses upon UV irradiation. For this purpose, we have constructed adenoviral vectors carrying the marsupial CPD-photolyase and plant 6-4PP-photolyase. So far, we have been able to demonstrate that both CPDs and 6-4PPs play important roles in cell death pathways in NER-deficient human fibroblasts, while CPDs are the major signals that lead NER-proficient human cells to death. At this time, we have been employing these recombinant adenoviral vectors for studying the effects of CPDs and 6-4PPs in cellular processes such as DNA replication and RNA transcription, which are inhibited by UV irradiation. Publications1.Armelini MG, LIMA-BESSA KM, Marchetto MC, Muotri AR, Chiganças V, Leite RA, Carvalho H, Menck CF. Exploring DNA damage responses in human cells with recombinant adenoviral vectors. Hum Exp Toxicol, v. 26, n. 11, p. 899-906, 2007. |