Isolamento e caracterização de elementos transponíveis em espécies do gênero Brycon (Characidae, Bryconinae)
Carregando...
Data
2012-04-20
Autores
Silva, Jésica Ruiz [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Grande parte do genoma dos eucariotos é composta de múltiplas cópias de DNA, conhecidas como DNAs repetitivos, cuja função em relação à manutenção, estrutura e funcionamento do genoma ainda precisa ser melhor investigada. Os DNAs repetitivos classificados como elementos transponíveis vêm sendo considerados como um dos principais representantes do genoma de vertebrados e, de maneira particular, os peixes têm chamado atenção em relação à grande diversidade de classes destes elementos encontradas em seus genomas. Visando ampliar os dados acerca de elementos transponíveis em peixes, o presente trabalho teve como objetivos o isolamento e a caracterização de retrotransposons da família Rex em duas espécies de Characidae - Brycon amazonicus e B. orbignyanus - e realizar inferências acerca de sua organização e dinâmica evolutiva. Desta forma, amostras de DNA foram utilizadas em PCR (Polymerase Chain Reaction) para amplificar segmentos dos retroelementos Rex1, Rex3 e Rex6 e os fragmentos obtidos foram clonados e sequenciados. Adicionalmente, estes segmentos de DNA foram utilizados como sondas em experimentos de hibridação in situ visando identificar a localização cromossômica destes retrotransposons. A identificação de elementos Rex em B. cephalus e B. orbignyanus demonstrou a presença destes retrotransposons não-LTR (Long Terminal Repetition) em um maior número de espécies de Characiformes e, especificamente, no grupo Characidae. Os segmentos analisados de Rex1 e Rex3 correspondem aos domínios codificantes 3-7 e 1, 2, 2A, A e B do gene da transcriptase reversa (RT), respectivamente. O fragmento de DNA relativo ao retroelemento Rex6 isolado codifica a porção C-terminal de uma endonuclease. Comparações entre sequências nucleotídicas de diferentes espécies de peixes...
A huge part of the eukaryote genome is constituted by multiple DNA copies, known as repetitive DNAs, which role regarding to the maintenance, structure, and function of the genome needs to be better understandable. The repetitive DNAs that are classified as transposable elements have been considered one of the main parts of the vertebrate genome and, particularly, fishes have gain attention due to the presence of many different classes of these elements in their genomes. In order to improve data on fish transposable elements, the present work intent to isolate and characterize retrotransposons of the Rex family in two Characidae species - Brycon amazonicus and B. orbignyanus - and infer on the organization and evolutionary dynamics of these elements. Therefore, DNA samples were used on PCR (Polymerase Chain Reaction) in order to amplify segments of the Rex1, Rex3, and Rex6 elements, and the obtained fragments were cloned and sequenced. Additionally, these DNA segments were used as probes throughout in situ hybridization procedures to identify the chromosome localization of these retrotransposons. The identification of Rex elements in B. cephalus e B. orbignyanus evidenced the presence of these non-LTR (Long Terminal Repetition) retrotransposons in a large number of Characiformes species and, specifically, in Characidae. The analyzed fragments of Rex1 and Rex3 correspond to the coding domains 3-7 and 1, 2, 2A, A and B of the reverse transcriptase (RT) gene, respectively. The DNA segment correlated to the Rex6 element codifies a C-terminal portion of an endonuclease. Nucleotide sequence comparisons among different fish species showed that these regions are highly conserved in diverse groups. Although the obtained data for B. amazonicus seemed to point to a higher similarity between Rex1 and Rex3 of... (Complete abstract click electronic access below)
A huge part of the eukaryote genome is constituted by multiple DNA copies, known as repetitive DNAs, which role regarding to the maintenance, structure, and function of the genome needs to be better understandable. The repetitive DNAs that are classified as transposable elements have been considered one of the main parts of the vertebrate genome and, particularly, fishes have gain attention due to the presence of many different classes of these elements in their genomes. In order to improve data on fish transposable elements, the present work intent to isolate and characterize retrotransposons of the Rex family in two Characidae species - Brycon amazonicus and B. orbignyanus - and infer on the organization and evolutionary dynamics of these elements. Therefore, DNA samples were used on PCR (Polymerase Chain Reaction) in order to amplify segments of the Rex1, Rex3, and Rex6 elements, and the obtained fragments were cloned and sequenced. Additionally, these DNA segments were used as probes throughout in situ hybridization procedures to identify the chromosome localization of these retrotransposons. The identification of Rex elements in B. cephalus e B. orbignyanus evidenced the presence of these non-LTR (Long Terminal Repetition) retrotransposons in a large number of Characiformes species and, specifically, in Characidae. The analyzed fragments of Rex1 and Rex3 correspond to the coding domains 3-7 and 1, 2, 2A, A and B of the reverse transcriptase (RT) gene, respectively. The DNA segment correlated to the Rex6 element codifies a C-terminal portion of an endonuclease. Nucleotide sequence comparisons among different fish species showed that these regions are highly conserved in diverse groups. Although the obtained data for B. amazonicus seemed to point to a higher similarity between Rex1 and Rex3 of... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Peixe - Genetica, Characideo, Brycon, Reação em cadeia de polimerase, Fishes
Como citar
SILVA, Jésica Ruiz. Isolamento e caracterização de elementos transponíveis em espécies do gênero Brycon (Characidae, Bryconinae). 2012. 73 f. Dissertação (mestrado) - Universidade Estadual Paulista Julio de Mesquita Filho, Instituto de Biociências de Botucatu, 2012.