| 1. |
- Hansson, Gunnar C., 1951, et al.
(författare)
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Molecular cloning of a cDNA coding for a region of an apoprotein from the 'insoluble' mucin complex of rat small intestine.
- 1994
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Ingår i: Biochemical and biophysical research communications. - 0006-291X. ; 198:1, s. 181-90
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Tidskriftsartikel (refereegranskat)abstract
- The major part of rat small intestinal mucins occurs as an 'insoluble' glycoprotein complex unextractable in 6 M guanidinium chloride unless disulfide bonds are cleaved. One of the trypsin-resistant high-glycosylated domains of this complex (glycopeptide A) was recently isolated. We have now deglycosylated it with HF, injected it into rabbits and the obtained antiserum was used for expression cloning providing a cDNA clone (VR-1A). This clone contained an open reading frame of 235 amino acids composed of two regions. The deduced N-terminal 53 amino acids included seven Cys residues and only one Ser, followed by a region of 182 residues with 64% Ser and Thr but devoid of Cys residues. Analysis of mRNA revealed a transcript of about 12 kb, identical in size to a band labelled with a probe based on the rat mucin-like protein (MLP/Muc2) cDNA. Pulsed-field gel electrophoresis of genomic rat DNA showed identical bands (380 and 500 kb) when blots were sequentially probed with the MLP/Muc2 probe and VR-1A. A panel of mouse x rat hybrids was used to localize the gene corresponding to both VR-1A and Muc2 to rat chromosome 1. The results strongly suggest that the 'insoluble' mucin complex of the rat small intestine is encoded by the Muc2 gene.
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| 2. |
- Klinga-Levan, Karin, 1974, et al.
(författare)
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Chromosomal mapping of three mucin genes in the rat.
- 1996
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Ingår i: Mammalian genome : official journal of the International Mammalian Genome Society. - 0938-8990. ; 7:3, s. 248-50
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Malmberg, Emily, 1978, et al.
(författare)
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Increased levels of mucins in the cystic fibrosis mouse small intestine, and modulator effects of the Muc1 mucin expression.
- 2006
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Ingår i: American journal of physiology. Gastrointestinal and liver physiology. - : American Physiological Society. - 0193-1857 .- 1522-1547. ; 291:2, s. G203-10
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Tidskriftsartikel (refereegranskat)abstract
- The mouse model (Cftr(tm1UNC)/Cftr(tm1UNC)) for cystic fibrosis (CF) shows mucus accumulation and increased Muc1 mucin mRNA levels due to altered splicing (Hinojosa-Kurtzberg AM, Johansson MEV, Madsen CS, Hansson GC, and Gendler SJ. Am J Physiol Gastrointest Liver Physiol 284: G853-G862, 2003). However, it is not known whether Muc1 is a major mucin contributing to the increased mucus and why CF/Muc1-/- mice show lower mucus accumulation. To address this, we have purified mucins from the small intestine of CF mice using guanidinium chloride extraction, ultracentrifugation, and gel filtration and analyzed them by slot blot, gel electrophoresis, proteomics, and immunoblotting. Normal and CF mice with wild-type (WT) Muc1 or Muc1-/- or that are transgenic for human MUC1 (MUC1.Tg, on a Muc1-/- background) were analyzed. The total amount of mucins, both soluble and insoluble in guanidinium chloride, increased up to 10-fold in the CF mice compared with non-CF animals, whereas the CF mice lacking Muc1 showed intermediate levels between the CF and non-CF mice. However, the levels of Muc3 (orthologue of human MUC17) were increased in the CF/Muc1-/- mice compared with the CF/MUC1.Tg animals. The amount of MUC1 mucin was increased several magnitudes in the CF mice, but MUC1 did still not appear to be a major mucin. The amount of insoluble mucus of the large intestine was also increased in the CF mice, an effect that was partially restored in the CF/Muc1-/- mice. The thickness of the firmly adherent mucus layer of colon in the Muc1-/- mice was significantly lower than that of WT mice. The results suggest that MUC1 is not a major component in the accumulated mucus of CF mice and that MUC1 can influence the amount of other mucins in a still unknown way.
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| 4. |
- Olson, Fredrik J., 1975, et al.
(författare)
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Blood group A glycosyltransferase occurring as alleles with high sequence difference is transiently induced during a Nippostrongylus brasiliensis parasite infection.
- 2002
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Ingår i: The Journal of biological chemistry. - 0021-9258. ; 277:17, s. 15044-52
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Tidskriftsartikel (refereegranskat)abstract
- Neutral mucin oligosaccharides from the small intestine of control rats and rats infected with the parasite Nippostrongylus brasiliensis were released and analyzed by gas chromatography-mass spectrometry. Infected animals expressed seven blood group A-like structures that were all absent in the control animals. The blood group A nature of these epitopes was confirmed by blood group A reactivity of the prepared mucins, of which Muc2 was one. Transferase assays and Northern blotting on small intestines from infected animals showed that an alpha-N-acetylgalactosaminyltransferase similar to the human blood group A glycosyltransferase had been induced. The expression was a transient event, with a maximum at day 6 of the 13-day-long infection. The rat blood group A glycosyltransferase was cloned, revealing two forms with an amino acid similarity of 95%. Both types had blood group A transferase activity and were probably allelic because none of 12 analyzed inbred strains carried both types. The second type was found in outbred rats and in one inbred strain. First generation offspring of inbred rats of each type were heterozygous, further supporting the allelic hypothesis. The transient induction and the large allelic variation could suggest that glycosyltransferases are part of a dynamic system altering mucins and other glycoconjugates as a protecting mechanism against microbial challenges.
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| 5. |
- Persson, Jonas, et al.
(författare)
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Molecular evolution of specific human antibody against MUC1 mucin results in improved recognition of the antigen on tumor cells.
- 2009
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Ingår i: Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine. - : Springer Science and Business Media LLC. - 1423-0380 .- 1010-4283. ; 30:4, s. 221-31
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Tidskriftsartikel (refereegranskat)abstract
- The MUC1 mucin is differentially expressed and glycosylated in cancer tissue as opposed to healthy tissue. Due to these differences, MUC1 is considered a potential biomarker suitable for cancer diagnosis and therapy. In a previous study, the human MUC1-specific antibody 12ESC-6 was able to bind a sequence variant of the tandem repeat of MUC1 that is not recognized by many other MUC1-specific antibodies. It was also found to bind efficiently to MUC1-carrying cells. We have now used 12ESC-6 as starting point for random mutagenesis to isolate variants with improved ability to bind MUC1 in human tumor tissue. The resulting 12ESC-6 variants were shown to recognize not only the naked MUC1 tandem repeat but even more so glycosylated variants thereof, in particular those carrying the GalNAc (Tn) glycoform. Selected variants of 12ESC-6 demonstrated improved staining of MUC1 on cell lines using flow cytometry and improved staining of the antigen in breast tumor tissue by immunohistochemistry. Molecular evolution and specific fine-tuning thus have the potential to improve the performance of antibody specificities targeting tumor-associated epitopes on MUC1 mucin.
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| 6. |
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| 7. |
- Thomsson, Kristina A, 1969, et al.
(författare)
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Intestinal mucins from cystic fibrosis mice show increased fucosylation due to an induced Fucalpha1-2 glycosyltransferase.
- 2002
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Ingår i: The Biochemical journal. - 0264-6021. ; 367:Pt 3, s. 609-16
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Tidskriftsartikel (refereegranskat)abstract
- In gene-targeted mouse models for cystic fibrosis (CF), the disease is mainly manifested by mucus obstruction in the intestine. To explore the mucus composition, mucins insoluble and soluble in 6 M guanidinium chloride were purified by three rounds of isopycnic ultracentrifugation from the small and large intestines of CF mice (Cftr(m1UNC)/Cftr(m1UNC)) and compared with wild-type mice. The amino acid composition was typical of that for mucins and showed increased amounts of the insoluble (2.5-fold increase) and soluble (7-fold increase) mucins in the small intestine of the CF mice compared with wild-type mice. Mucins from the large intestine of both wild-type and CF mice showed a high but constant level of fucosylation. In contrast, the insoluble and soluble mucins of the small intestine in CF mice revealed a large increase in fucose, whereas those of wild-type mice contained only small amounts of fucose. This increased fucosylation was analysed by releasing the O-linked oligosaccharides followed by GC-MS. NMR spectroscopy revealed that the increased fucosylation was due to an increased expression of blood group H epitopes (Fucalpha1-2Gal-). Northern-blot analysis, using a probe for the murine Fucalpha1-2 fucosyltransferase (Fut2), showed an up-regulation of this mRNA in the small intestine of the CF mice, suggesting that this enzyme is responsible for the observed increase in blood group H-type glycosylation. The reason for this up-regulation could be a direct or indirect effect of a non-functional CF transmembrane conductance regulator (CFTR) caused by the absence of CFTR channel.
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