Lars Berglund

The gene structure of tetranectin, a plasminogen binding protein.

The gene for human tetranectin was isolated from a genomic library with a mixture of degenerate oligonucleotide probes. The gene is about 12 kbp and contains two intervening sequences. The gene encodes a protein of 202 amino acid residues, with a signal peptide of 21 amino acid residues, followed by the tetranectin sequence of 181 amino acid residues. Northern blot analysis revealed that tetranectin mRNA was present in all eight tissues tested with the highest concentration in lung. Southern blot analysis showed hybridization to two genes. Further investigations are needed to determine whether the genes are allelic or non‐allelic.

Characterization of a bovine mammary gland PP3 cDNA reveals homology with mouse and rat adhesion molecule GlyCAM-1.

A full length PP3 (Proteose-Peptone component 3) cDNA of 679 bp was isolated from a bovine mammary gland cDNA library. The cDNA encodes a signal peptide of 18 amino acids followed by the mature PP3 sequence of 135 amino acids. This polypeptide showed homology with mouse and rat GlyCAM-1 (Glycosylation dependent Cell Adhesion Molecule 1) a protein which has been shown to act as a ligand for lymphocytes. The similarity was most profound between the signal peptides and three short regions of the mature polypeptides. Additionally structural conservation was predicted by computer analysis in the shape of a C-terminal amphipathic helix. PP3 was found to be expressed in mammary gland but not in peripheral lymph nodes, Peyers pathes, lung, spleen, heart, and muscle.

Structural characterization of bovine CD36 from the milk fat globule membrane

Bovine CD36 from milk fat globule membranes was characterized and a full-length CD36 cDNA of 2772 nucleotides was isolated from a bovine mammary gland cDNA library. The deduced protein sequence contains 472 amino acid residues with 82-84% identity to the amino acid sequences of CD36 from other species. Peptides corresponding to 43% of the protein were sequenced. All eight potential N-glycosylation sites were glycosylated and the carbohydrate compositions of the individual sites were determined.

A PROLINE-RICH CHITINASE FROM BETA VULGARIS

A gene (Chl) encoding a novel type of chitinase was isolated from Beta vulgaris. The Ch1 protein consists of an N-terminal hydrophobic prepeptide of 25 amino acids followed by a hevein-like domain of 22 amino acid residues, an unusually long proline-rich domain of 131 amino acid residues with 90 prolines, and finally a catalytic domain of 261 amino acid residues. Proteins with similar proline-rich domains are present in some other plants. The Chl gene shows a transient expression in response to fungal infection.

Cloning of a cDNA encoding murine tetranectin

A full-length cDNA encoding murine tetranectin (TN) was isolated and cloned from a murine lung lambda ZAPII cDNA library. The complete nucleotide sequence was determined revealing an open reading frame encoding 202 amino acids (aa) including a signal peptide of 21 aa. An overall aa identity of 79% exists between the deduced aa sequences of human and murine TN, revealing a high evolutionary conservation of the protein. The highest expression of mouse TN was found in lung and skeletal muscle.

Cloning and characterization of the bovine plasminogen cDNA

Abstract A bovine liver cDNA library was screened with oligonucleotide probes based on a partial bovine plasminogen cDNA sequence (Malinowski et al. , 1984, Biochemistry , 23 , 4243–4250). Several cDNA clones were isolated and the nucleotide sequence revealed the amino acid sequence for plasminogen except for 21 N -terminal residues. The amino acid sequence of the N -terminal region and the pre-peptide was established after cloning and sequencing primer extension products. The cDNA has two possible start methionines, giving rise to pre-peptides of 26 and 19 amino acid residues, respectively, followed by the mature plasminogen sequence of 786 amino acid residues. Three amino acid substitutions were found when the cDNA encoded protein was compared with the bovine protein sequence. Northern blotting analysis showed that plasminogen is expressed in liver but not in mammary gland, skeletal muscle and heart. The lack of plasminogen expression in mammary gland was confirmed by the screening of a bovine mammary gland cDNA library with a bovine plasminogen cDNA probe, since no positive clones were detected.

Lectins interact differentially with purified human eosinophils, cultured cord blood‐derived mast cells and the myeloid leukaemic cell line AML14.3D10: induction of interleukin‐4 secretion is conserved among granulocytes, but is not proportional to agglutination or lectin–glycoprotein interaction

Background Atopy is closely associated with the cellular T helper type‐2 (Th2) phenotype, that is dominated by the pleiotrophic cytokine IL‐4. The cellular source of IL‐4 has yet to be determined, although basophils have been proposed. Eosinophils and mast cells are likely contenders investigated here, and the eosinophil‐like leukaemia line AML14.3D10 is compared to eosinophils as an in vitro culturable model for eosinophils. Lectins can cross‐link‐specific surface glycoproteins and are found in the ingested (processed foods) and inhaled (airborne pollen grains) human environment. Therefore it is of interest to determine whether lectins can elicit the release of IL‐4 from Th2‐associated granulocytes other than basophils.

Cloning and characterization of the bovine plasminogen activators uPA and tPA

Abstract A bovine cDNA library was screened with cDNA probes coding for the two human plasminogen activators, uPA and tPA. An almost full-length uPA cDNA and a fulllength tPA cDNA were isolated and sequenced. The almost full-length uPA cDNA of 2228 bp codes for nine amino acids of the signal peptide and the 413 amino acids of the bovine pro uPA. Bovine and human uPA had 81% identical nucleotides and 75% identical amino acids. The tPA cDNA of 2402 bp codes for a prepro protein of 562–566 amino acids. The exact length of the protein depends on which of three putative translational start sites is used. The similarity to human tPA was 78% at the nucleotide level and 82% at the amino acid level. Northern blots could not detect the expression of either uPA or tPA in normal lactating udder. In RNA from a mastitic udder, low levels of both uPA mRNA and tPA mRNA were detected.

Primary structure of bovine α2-antiplasmin

The primary structure of bovine α2‐antiplasmin (α2AP) has been determined from cDNA and partial peptide sequencing. Mature bovine α2AP contains 470 residues and is 6 residues longer than human α2 AP. Alignment of the two protein sequences show that 81% of their amino acid residues are identically located. Bovine α2AP has 5 N‐linked carbohydrate groups, of which four are found in human α2AP (AsnlOS, 274,288 and 295). Asn227 is the fifth carbohydrate attachement site in bovine α2AP. The 3 Cys residues of bovine α2AP are present as an unpaired residue (Cys131) and as a pair in a disulfide bridge (Cys49‐Cys12). The assignment of the bridge in bovine α2AP is at variance with the previous assignment of the two disulfide bridges in human α2AP [Lijnen, H.R. et al. (1987) Eur. J. Biochem. 166, 565‐574].