Banca de QUALIFICAÇÃO: NATHALIA MAÍRA CABRAL DE MEDEIROS

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : NATHALIA MAÍRA CABRAL DE MEDEIROS
DATA : 09/10/2017
HORA: 14:00
LOCAL: carl von dietrich
TÍTULO:

IDENTIFICATION AND CHARACTERIZATION FROM BASE EXCISION REPAIR PATHWAY COMPONENTS (BER) IN SUGARCANE (SACCHARUM spp.).

PALAVRAS-CHAVES:

DNA repair, Ap Endonuclease, Sugarcane, Phylogeny, Modeling

PÁGINAS: 250
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
SUBÁREA: Biologia Molecular
RESUMO:

The productivity of any cultivar is directly related to the stability of its genome. Then, if it suffers some lesion on its sequence, it may have important effect in its development or growth. The DNA repair is formed by different pathways and one of this is the base excision pathway (BER). In plants these studies are recently in special for model plants as Arabidopsis thaliana or rice. In this work it is presented the data for sugarcane that it is been used as a plant model by our group due to its economic importance. ScARP1 is a sequence homologous to Ap endonuclease from A. thaliana (AtARP). Then, the aim of this work is to understand the role of some sequences from BER pathway in sugarcane and in plants. This work use two approaches, for the first one it was biochemical characterization the ScARP1 and the second approach was to identify other components of the BER pathway in sugarcane and in plants in order to understand the conservation of these sequences in plants and in special in Poaceae. For the first approach, the ScARP1 protein was cloned, expressed and purified, after which it was subjected to different assays to evaluate its enzymatic efficiency (considering temperature, enzymatic cofactors and salt concentration), as well as the substrate that would be recognized by this enzyme. It was observed that the sugarcane Ap endonuclease has only AP endonuclease activity since it did not recognize other subtracts. In addition, the existence of enzymatic complementation with ScARP1 in extracts of A. thalina mutant arp ^{- / -} . It was observed a partial complementation for the AP endonuclease activity. For the second approach of this work, it was considered the previous results, where it was verified for the sequence AP endonuclease a duplication in sugarcane (ScARP1 and ScARP3). Based on these results, a search was made for reference sequences from the BER path in the UniProt database. These sequences were used as a basis for searching at the sugarcane databases: DFCI and SUCEST. The results of this search were aligned with other sequences of plant organisms from Phytozome, in order to identify possible duplications for the components of the BER pathway. The sequences were evaluated by the presence of conserved domains, some of these sequences were chosen for phylogenetic analysis and modeling process, then creating hypothetical models that are still in progress. The results obtained with this work extend a little more about BER pathway in sugarcane, and these results may be used in the future as biotechnological tools for the management of this cultivar of global importance for the production of sugar and biofuel.

MEMBROS DA BANCA:
Interno - 1880243 - DANIEL CARLOS FERREIRA LANZA
Externo ao Programa - 1893445 - EUZEBIO GUIMARAES BARBOSA
Presidente - 1513597 - JOAO PAULO MATOS SANTOS LIMA