Over-expression of the murine polymeric immunoglobulin receptor gene in the mammary gland of transgenic mice

• Published in: Transgenic research Vol. 8; no. 2; pp. 125 - 135
• Main Authors: DE GROOT, N, VAN KUIK-ROMEIJN, P, SANG HA LEE, DE BOER, H. A
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01-04-1999; Springer Nature B.V
• Subjects: Animals; Biological and medical sciences; Biotechnology; Blotting, Northern; Blotting, Southern; Cattle; Cell receptors; Cell structures and functions; Cloning, Molecular; Electrophoresis, Polyacrylamide Gel; Female; Fundamental and applied biological sciences. Psychology; Genes; Genetic engineering; Genetic technics; Immunoglobulin A, Secretory - metabolism; Lactation - metabolism; Mammary Glands, Animal - metabolism; Methods. Procedures. Technologies; Mice; Mice, Transgenic; Milk - metabolism; Miscellaneous; Molecular and cellular biology; Receptors, Polymeric Immunoglobulin - genetics; Receptors, Polymeric Immunoglobulin - metabolism; Rodents; Secretory Component - metabolism; Transcription, Genetic; Transgenic animals; Transgenic animals and transgenic plants; Up-Regulation; Secretory component; IgA; Immunoglobulins; Rodentia; Transgenic animal; Tissue specificity; Gene overexpression; Gene expression; Vertebrata; Mammalia; Mouse; Mammary gland; Biological receptor
• ISSN: 0962-8819; 1573-9368
• DOI: 10.1023/A:1008981312682

The polymeric immunoglobulin receptor (pIgR), a transmembrane protein, transports dimeric IgA (dIgA) across the epithelial cells of the mucosal surfaces into the external secretions, for example milk from the mammary glands. The pIgR is consumed during the transcytosis of dIgA and is cleaved at the apical side of the epithelial cells, regardless of the binding to its ligand (dIgA), to form secretory component (SC). We hypothesize that the expression level of the endogenous murine pIgR gene in the epithelial cells is rate-limiting for the transport of dIgA across the epithelial cells into the secretions. We address this key issue by generating transgenic mice over-expressing the pIgR gene in their mammary glands in order to examine the effect on dIgA levels in the milk. Here we report on the generation of transgenic mice and analysis of the expression level of pIgR in their mammary glands. We cloned and characterized the murine pIgR gene and constructed an expression cassette bearing the pIgR gene under the control of the regulatory sequences of the bovine alpha s1-casein gene. Four transgenic lines were made, expressing the pIgR construct at RNA and protein level only in their mammary glands. The levels of the SC protein in the milk ranged from 0.1 to 2.7 mg/ml during mid-lactation. These levels are 10-270 times higher than wild-type SC levels (0.01 mg/ml).