The Effect of Mammary Gland Expression of Human Lysozyme on the Properties of Milk from Transgenic Mice

• Published in: Journal of dairy science Vol. 78; no. 12; pp. 2645 - 2652
• Main Authors: Maga, E.A., Anderson, G.B., Murray, J.D.
• Format: Journal Article
• Language: English
• Published: Savoy, IL Elsevier Inc 01.12.1995; Am Dairy Sci Assoc; American Dairy Science Association
• Subjects: ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; ANIMAL TRANSGENIQUE; ANIMALES TRANSGENICOS; Animals; ARN MENSAJERO; ARN MESSAGER; Biological and medical sciences; Biotechnology; Caseins - genetics; Cattle; Chymosin - metabolism; COAGULACION; COAGULATION; COLLOIDE; COLOIDES; CONTENIDO PROTEICO; CUAJO; DIFERENCIAS BIOLOGICAS; DIFFERENCE BIOLOGIQUE; Elasticity; EXPRESION GENICA; EXPRESSION DES GENES; Female; Food industries; Fundamental and applied biological sciences. Psychology; Gene Expression; Genetic engineering; Genetic technics; GLANDE MAMMAIRE; GLANDULAS MAMARIAS; human lysozyme; Humans; LISOZIMA; LYSOZYME; Mammary Glands, Animal - metabolism; Methods. Procedures. Technologies; Mice; Mice, Transgenic; Micelles; milk; Milk - chemistry; Milk - physiology; Muramidase - genetics; PRESURE; Promoter Regions, Genetic; PROPIEDADES REOLOGICAS; PROPRIETE RHEOLOGIQUE; PROTEINAS DE LA LECHE; PROTEINE DU LAIT; Research and development. New food products, dietetic foods and beverages; RNA, Messenger - metabolism; TENEUR EN PROTEINES; transgenic; Transgenic animals; Transgenic animals and transgenic plants; Viscosity; human lysozyme; milk; transgenic; Human; Enzyme; Rodentia; Transgenic animal; Gene expression; Biological activity; Vertebrata; Mammalia; Mouse; Glycosidases; Hydrolases; Models; Mammary gland; Antibacterial agent; O-Glycosidases; Lysozyme; Milk
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(95)76894-1

Transgenic mice were used as model systems to evaluate the impact of human lysozyme expression in the mammary gland. We previously generated two lines of transgenic mice that express human lysozyme mRNA in the mammary gland under the tissue-specific and developmentally correct control of the bovine gene promoter for αs1-casein. Concentrations of human lysozyme protein in milk of transgenic mice varied from .25 to .71μg/μl of milk. Human lysozyme secreted into mouse milk retained its antimicrobial activity, as determined by a denaturing polyacrylamide gel activity assay. The physical and functional properties of the milk were also altered, because mouse milk containing human lysozyme had a 35% decrease in rennet clotting time, a smaller median micelle size (157nm vs. 172nm), and a 2.5– to 3-fold greater gel strength than control milk. From these results, we conclude that the use of transgenic animals producing lysozyme in the milk is feasible and potentially useful to the dairy industry.