Bovine Muc1 is a highly polymorphic gene encoding an extensively glycosylated mucin that binds bacteria

Sando, L., Pearson, R., Gray, C., Parker, P., Hawken, R., Thomson, P. C., Meadows, J. R. S., Kongsuwan, K., Smith, S. and Tellam, R. L. (2009) Bovine Muc1 is a highly polymorphic gene encoding an extensively glycosylated mucin that binds bacteria. Journal of Dairy Science, 92 10: 5276-5291. doi:10.3168/jds.2009-2216


Author Sando, L.
Pearson, R.
Gray, C.
Parker, P.
Hawken, R.
Thomson, P. C.
Meadows, J. R. S.
Kongsuwan, K.
Smith, S.
Tellam, R. L.
Title Bovine Muc1 is a highly polymorphic gene encoding an extensively glycosylated mucin that binds bacteria
Formatted title
Bovine Muc1 is a highly polymorphic gene encoding an extensively glycosylated mucin that binds bacteria
Journal name Journal of Dairy Science   Check publisher's open access policy
ISSN 0022-0302
1525-3198
Publication date 2009-10
Sub-type Article (original research)
DOI 10.3168/jds.2009-2216
Open Access Status
Volume 92
Issue 10
Start page 5276
End page 5291
Total pages 16
Place of publication New York, United States
Publisher Elsevier
Language eng
Formatted abstract
The bovine Muc1 protein is synthesized by mammary epithelial cells and shed into milk as an integral component of the milk fat globule membrane; however, the structure and functions of this mucin, particularly in relation to lactation, are poorly defined. The objectives of this investigation were to investigate the Muc1 gene and protein structures in the context of lactation and to test the hypothesis that Muc1 has a role in innate immune defense. Polymerase chain reaction analysis of genomic DNA from 630 cattle revealed extensive polymorphism in the variable number of tandem repeats (VNTR) in the bovine Muc1 gene. Nine allelic variants spanning 7 to 23 VNTR units, each encoding 20 AA, were identified. Three alleles, containing 11, 14, and 16 VNTR units, respectively, were predominant. In addition, a polymorphism in one of the VNTR units has the potential to introduce a unique site for N-linked glycosylation. Statistical analysis indicated weak associations between the VNTR alleles and milk protein and fat percentages in a progeny-tested population of Holstein-Friesian dairy cattle. No association with somatic cell count could be demonstrated. Bovine Muc1 was purified from milk fat globule membranes and characterized. The protein was highly glycosylated, primarily with O-linked sialylated T-antigen [Neu5Ac(α2-3)-Gal(β1-3)-GalNAcα1] and, to a lesser extent, with N-linked oligosaccharides, which together accounted for approximately 60% of the apparent mass of Muc1. Purified bovine Muc1 directly bound fluorescently labeled Escherichia coli BioParticles (Invitrogen, Mount Waverley, Australia) and inhibited their binding to bovine mammary epithelial cells grown in vitro. It was also demonstrated that the expression of Muc1 mRNA in bovine mammary epithelial cells was markedly upregulated by lipopolysaccharide. Muc1 may be a pattern recognition protein that has the capacity to sequester bacteria and prevent their attachment to epithelial surfaces by immobilizing and subsequently shedding Muc1-bound bacteria from the cell surface. It was concluded that bovine Muc1 is probably an inducible innate immune effector and an important component of the first line of defense against bacterial invasion of epithelial surfaces, particularly mammary epithelial surfaces and the neonatal gut.
Keyword Innate immunity
Muc1
Mucin
Polymorphism
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Veterinary Science Publications
 
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