Submitted to: Biomed Central (BMC) Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/7/2011
Publication Date: 3/7/2011
Citation: Hoorens, P.R., Rinaldi, M., Li, R.W., Goddeeris, B., Claerebout, E., Vercruysse, J., Geldhof, P. 2011. Genome wide analysis of the bovine mucin genes and their gastrointestinal transcription profile. Biomed Central (BMC) Genomics. 12:140. Interpretive Summary: Parasitic nematodes are among major causal agents contributing to production inefficiencies in the cattle industry. Parasitic nematode infection elicits drastic changes in gene expression patterns in host cells. In this study, we examined genomic structures of mucins and their tissue-specific expression patterns. The mucosa of the GI tract showed to have a specific pattern of mucin expression in the organs examined, suggesting that the mucin family components may play an important role as first defense line in cattle. Our results provided insight into the roles that mucins play in protective immunity against nematode infection in the bovine gastrointestinal tract.
Technical Abstract: Mucins are large glycoproteins implicated in protection of all mucosal surfaces. In humans and rodents, the mucin gene family has been well described and previous studies have investigated the distribution and function of mucins in the respiratory, urogenital and gastrointestinal (GI) tracts. In contrast, little data is available in ruminant species, including cattle. The current study first gives a comprehensive overview of all members of the bovine mucin family identified through database analysis. Secondly, the transcription pattern of these mucins in the bovine GI tract is investigated. Nine bovine membrane-associated mucins (MUC1, MUC3A, MUC4, MUC12, MUC13, MUC15, MUC20 and MUC21) and eight secreted mucins (MUC2, MUC5AC, MUC5B, two partial MUC6, MUC7, MUC19 and BSM) were identified. New sequences mRNA and/or gDNA have been composed and submitted to EMBL database for MUC2, MUC5AC, MUC5B, MUC16 and MUC19. Few differences in the transcription profile between humans and cattle were observed; such as MUC5B, which was not found to be transcribed in either the oesophagus or in the abomasum (‘true stomach’) while it has been observed in human oesophageal submucosal glands and stomach. In the pre-stomachs, only three membrane-associated mucins (MUC1, MUC16 and MUC20) and no secreted mucins were found to be transcribed. Differences in mucin distribution have been described between the fundic and the pyloric region of human stomach, but in cattle, no differences were observed with the exception of MUC15 that was found to be transcribed in the fundic region of all the animals sampled but not in the pyloric part. Putative bovine homologues were identified for all members of the human mucin family, with the exception of human MUC3B, MUC8 and MUC17, which to date, have not been identified in any other species. Domain architecture of the membrane-associated mucins was found to be similar between humans and cattle, while protein architecture of the gel-forming mucins appeared to be less conserved, therefore further studies will be necessary to understand if dissimilarity in domain composition and order may result in the formation of a mucus layer that has different biological and rheological properties in ruminants compared to non ruminant species. At transcription level, similar to what has been described in humans, the mucosa of the GI tract showed to have a specific pattern of mucin expression in the organs examined, suggesting that the mucin family components may play an important role as first defense line in cows as in humans.