Studio dell'espressione del gene SREBP-1 e sue relazioni con la componente lipidica del latte ovino

Sterol Regulator Element Binding Proteins (SREBPs) are a family of transcription factors that plays a central role in lipids synthesis in mammary gland. The main aims of this research were: to develop a method for RNA extraction from milk somatic cells without damaging the mammary gland; to study SREBP-1 gene expression in the Sarda breed sheep in the first stage of lactation; and to correlate it to fatty acids in milk. In order to develop extraction method 4 milk samples were collected weekly from 15 sheep. The first 3 samples were analysed within 4 hours of collection, while the last one was divided into 2 aliquots of 150ml; one of this was analysed within 4 h and the other one at 24h. Twenty sheep have been used for the SREBP1 gene expression study with RTqPCR and from each ewe two milk samples at 40 and 70 days of lactation were collected. These samples were used for RNA extraction and for fatty acids quantification with gas chromatography method. The developed method has shown to be reliable and repeatable; 150ml of milk are enough to provide good amount and quality of RNA, suitable for study of gene expression. SREBP -1 gene expression showed a positive correlation with the fat yield (P<0,001) while no correlation with the range of fatty acid was found. The relationship between SREBP-1 gene and the amount of fat yield suggests the importance of this gene for lipids synthesis mechanism in mammary gland.