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

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journal contribution
posted on 2009-01-01, 00:00 authored by L Sando, R Pearson, C Gray, Phillip Parker, R Hawken, P Thomson, J Meadows, K Kongsuwan, Stuart Smith, R Tellam
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.

History

Journal

Journal of dairy science

Volume

92

Pagination

5276 - 5291

Location

Champaign, Ill.

Open access

  • Yes

ISSN

0022-0302

eISSN

1525-3198

Language

eng

Notes

Ulrich's checked. Peer reviewed. rc 18/01/10

Publication classification

C1 Refereed article in a scholarly journal

Copyright notice

2009, American Dairy Science Association