Expressão de genes e proteínas relacionados à deposição de gordura intramuscular em bovinos Nelore
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2019-08-23
Autores
Salatta, Bruna Maria
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Universidade Estadual Paulista (Unesp)
Resumo
Produtos cárneos que contenham propriedades organolépticas específicas e que atendam às exigências dos consumidores, são cada vez mais valorizados no mercado. Apesar da sua importância, as características de qualidade da carne em geral não são consideradas em programas de melhoramento genético animal, em razão do alto custo e dificuldade de mensuração. Marcadores moleculares identificados em análises genômicas, têm sido estudados em rebanhos Nelore. Trabalhos que visam o entendimento da expressão de genes e proteínas envolvidos na determinação de características relacionadas a gordura intramuscular da carne, são realizados com o intuito de auxiliar no entendimento da expressão dos genes relacionados a possíveis biomarcadores. Assim, inúmeros trabalhos que visam avaliar a expressão diferencial de genes podem ser encontrados na literatura, no entanto, devido a divergências entre o manejo e as raças estudadas, os resultados são discordantes, e a validação dos genes mais comumente encontrados, se faz necessário para que essas informações possam ser úteis em programas de melhoramento genético. Assim, este estudo teve como finalidade buscar na literatura genes diferencialmente expressos associados à característica de deposição de gordura intramuscular, avaliada por meio de duas técnicas, e validá-los em uma população de bovinos Nelore com fenótipo extremo para a característica gordura intramuscular por meio da técnica de PCR quantitativa em tempo real. Além disto, foi verificado se os genes diferencialmente expressos estão sendo traduzidos em proteínas diferencialmente expressas, por meio da técnica de espectrometria de massas avançada (LCMS/MS). Para isso, foram selecionadas 24 amostras divergentes para cada método de avaliação de deposição de gordura. F0oram selecionados 5 genes para o método do escore visual (FABP4, DAGT1, DGAT2, SCD e PPARG) e oito genes para o conteúdo lipídico, medidos pelo método químico (SREBF1, LPL, ACACA, BARX2, EGR1, CDS1, STAT5A e HTATIP2). Foram observadas diferenças significativas nos níveis de expressão dos genes FABP4, DGAT1, DGAT2, BARX2, STAT5A e SDC. Além disso, as proteínas PRDM1 e CO1A2, reguladas pelo fator de transcrição STAT5A parecem exercer papel importante no processo de deposição de gordura intramuscular, podendo ser possíveis marcadores moleculares para o melhoramento dessa característica. Em relação às demais proteínas não identificadas em nossos estudos, os resultados sugerem a importância dos mecanismos póstranscricionais e pós-traducionais na regulação do metabolismo.
Meat products with specific organoleptic properties and that attend the requirements of consumers, are increasingly valued in the market. Despite its importance, meat quality traits have not been widely used in animal breeding programs because of the high cost and difficulty of measurement. Molecular markers identified in genomic analyzes have been studied in Nellore herds. Studies aimed at understanding the expression of genes and proteins involved in the determination of characteristics such as intramuscular fat from meat are performed with the aim of helping to understand the expression of the genes related to possible biomarkers. Several studies that aim the expression of differentially expressed genes can be found in the literature, however, because of differences between management and breeds studied the results are discordant, and the validation of the common genes found is necessary for this information to be useful in breeding programs. Thus, this study aimed to search the literature for differentially expressed genes related to the marbling trait, by means of the two techniques for the evaluation of this trait and to validate them in a commercial herd of Nellore cattle, by quantitative real time PCR techniques. Besides that, this study will verify if the differentially expressed genes are being translated into differentially expressed proteins, using advanced mass spectrometry technique (LC-MS/MS). For this, 24 divergent samples were selected for each intramuscular fat deposition evaluation method. Five genes were selected for the marbling, measured by visual score method (FABP4, DAGT1, DGAT2, SCD and PPARG) and eight genes for the lipid content, measured by the chemical method (SREBF1, LPL, ACACA, BARX2, EGR1, CDS1, STAT5A and HTATIP2). Significant differences in expression levels of FABP4, DGAT1, DGAT2, BARX2, STAT5A and SDC were observed. In addition, the PRDM1 and CO1A2 proteins, regulated by the transcription factor STAT5A, seem to play an important role in the intramuscular fat deposition process, and molecular markers may be possible to improve this characteristic. Regarding the other unidentified proteins in our studies, the results suggest the importance of post-transcriptional and post-translational mechanisms in the regulation of metabolism.
Meat products with specific organoleptic properties and that attend the requirements of consumers, are increasingly valued in the market. Despite its importance, meat quality traits have not been widely used in animal breeding programs because of the high cost and difficulty of measurement. Molecular markers identified in genomic analyzes have been studied in Nellore herds. Studies aimed at understanding the expression of genes and proteins involved in the determination of characteristics such as intramuscular fat from meat are performed with the aim of helping to understand the expression of the genes related to possible biomarkers. Several studies that aim the expression of differentially expressed genes can be found in the literature, however, because of differences between management and breeds studied the results are discordant, and the validation of the common genes found is necessary for this information to be useful in breeding programs. Thus, this study aimed to search the literature for differentially expressed genes related to the marbling trait, by means of the two techniques for the evaluation of this trait and to validate them in a commercial herd of Nellore cattle, by quantitative real time PCR techniques. Besides that, this study will verify if the differentially expressed genes are being translated into differentially expressed proteins, using advanced mass spectrometry technique (LC-MS/MS). For this, 24 divergent samples were selected for each intramuscular fat deposition evaluation method. Five genes were selected for the marbling, measured by visual score method (FABP4, DAGT1, DGAT2, SCD and PPARG) and eight genes for the lipid content, measured by the chemical method (SREBF1, LPL, ACACA, BARX2, EGR1, CDS1, STAT5A and HTATIP2). Significant differences in expression levels of FABP4, DGAT1, DGAT2, BARX2, STAT5A and SDC were observed. In addition, the PRDM1 and CO1A2 proteins, regulated by the transcription factor STAT5A, seem to play an important role in the intramuscular fat deposition process, and molecular markers may be possible to improve this characteristic. Regarding the other unidentified proteins in our studies, the results suggest the importance of post-transcriptional and post-translational mechanisms in the regulation of metabolism.
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Palavras-chave
Gordura intramuscular, Lc-ms/ms, Nelore, qRT-PCR, Validação, Intramuscular fat, Nellore, Validation