title: The construction and expression of lysine-rich gene in the mammary gland of transgenic mice.
abstract: Lysine is the limiting amino acid in cereal grains, which represent a major source of human food and animal feed worldwide, and is considered the most important of the essential amino acids. In this study, β-casein, αS2-casein, and lactotransferrin cDNA clone fragments encoding lysine-rich peptides were fused together to generate a lysine-rich (LR) gene and the mammary gland-specific expression vector pBC1-LR-NEO(r) was constructed. Transgenic mice were generated by pronuclear microinjection of the linearized expression vectors harboring the LR transgene. The transgenic mice and their offspring were examined using multiplex polymerase chain reaction (PCR), Southern blotting, reverse transcriptase-PCR, in situ hybridization, and Western blotting techniques. Our results showed that the LR gene was successfully integrated into the mouse genome and was transmitted stably. The specific LR gene expression was restricted to the mammary gland, active alveoli of the transgenic female mice during lactation. The lysine level of the two transgenic lines was significantly higher than that of nontransgenic controls (p<0.05). In addition, the growth performance of transgenic pups was enhanced by directly feeding them the LR protein-enriched transgenic milk. Our results demonstrated that lysine-rich gene was successfully constructed and expressed in mammary gland of transgenic mice. This study will provide a better understanding of how mammary gland expression systems that increase the lysine content of milk can be applied to other mammals, such as cows.
authors.affiliation: Jilin Provincial Key Laboratory of Animal Embryo Engineering, The Center for Animal Embryo Engineering of Jilin Province, College of Animal Science and Veterinary Medicine, Jilin University, Changchun, Jilin, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Ma
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.forename: Guangqi
authors.initials: G
authors.lastname: Song
authors.forename: Yue
authors.initials: Y
authors.lastname: Chen
authors.forename: Zhongwei
authors.initials: Z
authors.lastname: Wang
authors.forename: Yupeng
authors.initials: Y
authors.lastname: Yin
authors.forename: Delong
authors.initials: D
authors.lastname: Kong
authors.forename: Sheng
authors.initials: S
authors.lastname: Zhang
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Zhao
authors.forename: Hongsheng
authors.initials: H
authors.lastname: Ouyang
authors.forename: Bo
authors.initials: B
authors.lastname: Tang
authors.forename: Ziyi
authors.initials: Z
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D008239:Lysine; D008297:Male; D008321:Mammary Glands, Animal / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data
chemical_list: D008239:Lysine