title: Short communication: Altered expression of specificity protein 1 impairs milk fat synthesis in goat mammary epithelial cells.
abstract: Specificity protein 1 (encoded by SP1) is a novel transcription factor important for the regulation of lipid metabolism and the normal function of various hormones in model organisms. Its potential role, if any, on ruminant milk fat is unknown. Despite the lower expression of the lipolysis-related gene ATGL (by 44 and 37% respectively), both the adenoviral overexpression and the silencing of SP1 [via short interfering (si)RNA] markedly reduced cellular triacylglycerol (TAG) content (by 28 and 25%, respectively), at least in part by decreasing the expression of DGAT1 (-36% in adenovirus treatment) and DGAT2 (-81 and -87%, respectively) that are involved in TAG synthesis. Consistent with the markedly lower expression of genes related to lipid droplet formation and secretion (TIP47 by 19 and 32%, and ADFP by 25 and 25%, respectively), cellular lipid droplet content was also decreased sharply, by 9 and 8.5%, respectively, after adenoviral overexpression of SP1 or its silencing via siRNA. Overall, the results underscored a potentially important role of SP1 in maintaining milk-fat droplet synthesis in goat mammary epithelial cells.
authors.affiliation: Key Laboratory of Sichuan Province for Qinghai-Tibetan Plateau Animal Genetic Reservation and Exploitation, Southwest University for Nationalities, Chengdu, Sichuan, 610041, P. R. China; Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P. R. China.
authors.forename: J J
authors.initials: JJ
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Sichuan Province for Qinghai-Tibetan Plateau Animal Genetic Reservation and Exploitation, Southwest University for Nationalities, Chengdu, Sichuan, 610041, P. R. China. Electronic address: luojun@nwsuaf.edu.cn.
authors.forename: J
authors.initials: J
authors.lastname: Luo
authors.affiliation: Key Laboratory of Sichuan Province for Qinghai-Tibetan Plateau Animal Genetic Reservation and Exploitation, Southwest University for Nationalities, Chengdu, Sichuan, 610041, P. R. China.
authors.forename: H F
authors.initials: HF
authors.lastname: Xu
authors.affiliation: Key Laboratory of Sichuan Province for Qinghai-Tibetan Plateau Animal Genetic Reservation and Exploitation, Southwest University for Nationalities, Chengdu, Sichuan, 610041, P. R. China.
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.affiliation: Mammalian NutriPhysioGenomics, Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana 61801. Electronic address: jloor@illinois.edu.
authors.forename: J J
authors.initials: JJ
authors.lastname: Loor
mesh_terms: D000818:Animals; D051048:Diacylglycerol O-Acyltransferase / Q000235:genetics / Q000378:metabolism; D004041:Dietary Fats / Q000032:analysis*; D004847:Epithelial Cells / Q000378:metabolism*; D005786:Gene Expression Regulation; D020868:Gene Silencing; D006041:Goats; D008049:Lipase / Q000235:genetics / Q000378:metabolism; D066292:Lipid Droplets / Q000378:metabolism; D008066:Lipolysis; D008321:Mammary Glands, Animal / Q000166:cytology / Q000378:metabolism*; D008892:Milk / Q000737:chemistry*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D014280:Triglycerides / Q000378:metabolism
chemical_list: D004041:Dietary Fats; D034741:RNA, Small Interfering; D016329:Sp1 Transcription Factor; D014280:Triglycerides; D051048:Diacylglycerol O-Acyltransferase; D008049:Lipase
keywords: SP1; dairy goat; fat synthesis; lipid metabolism