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D M Au

Publications and source records attributed to D M Au.

6 recordsLinked to original sources
PubMed1995

Genomic organization and characterization of a three-gene rat adult beta-globin haplotype.

The isolation and detailed characterization of a three-beta-globin gene (GloB) haplotype in the Sprague-Dawley (S-D) rat is described. An enriched library, lambda SDHelib, was screened with a human GloB probe, humbg44, and from which a beta minor gene, Rathbbz, was isolated, sequenced and characterized. A S-D rat GloB-specific probe, Ratbgze12, derived from the Rathbbz gene, was then used to screen a S-D rat genomic library, lambda SDglib. The clone T1510 was isolated and identified to include the entire Rathbbz gene and part of another GloB gene, Rathbby, which was 5' upstream from Rathbbz. Chromosomal walking upstream using the riboprobe, rnaT71, led to the isolation of an overlapping clone, Ta49, which was shown to include two full-length GloB genes; the most 5' was Rathbbx followed by Rathbby. Sequence data suggests that Rathbbx is a beta major gene, whereas Rathbby is a hybrid gene of Rathbbx and Rathbbz. Genomic hybridization confirmed this particular three-gene haplotype in the S-D rat. This haplotype, a1, may be the prototype of the GloB cluster in rat.

Animals↗
PubMed1993

Two new rat alpha-globin sequences as identified by the conserved region PCR.

Based on the notion that regions of structural genes which encode critical domains of the corresponding proteins are highly conserved among closely related species, oligonucleotide primers were designed and used to amplify the alpha-globin sequence(s) of the Sprague-Dawley (SD) rat. Data of these amplified sequence constructs showed that two new rat alpha-globin specific sequences have been identified. Southern hybridization confirmed the presence of these sequences in the rat genome.

Animals↗
PubMed1991

A class of amphipathic proteins associated with lipid storage bodies in plants. Possible similarities with animal serum apolipoproteins.

The lipid-storing tissues of plants contain many small (0.2-1 microns) lipid (normally triacylglycerol) droplets which are surrounded and stabilized by a mixed phospholipid and protein annulus. The proteinaceous components of the lipid storage bodies are termed oleosins and are not associated with any other cellular structures. The major oleosins of rapeseed and radish have been isolated by preparative SDS-PAGE and are respectively classes of 19 kDa and 20 kDa proteins. Both protein classes were N-terminally blocked for direct sequencing, but were partially sequenced following limited proteolytic digestion. The major rapeseed oleosin was made up of at least two 19 kDa polypeptides, termed nap-I and nap-II, which have closely related but different amino acid sequences. A single 20 kDa oleosin, termed rad-I, was found in radish. A near full length cDNA clone for a major rapeseed oleosin was sequenced and found to correspond almost exactly to the sequence of nap-II. The sequences of nap-I and rad-I show very close similarity to one another, as do the sequences of nap-II and the previously determined sequence for the major oleosin from maize. All four oleosins have a large central hydrophobic domain flanked by polar N- and C-terminal domains. Secondary structure predictions for the four oleosins are similar and a novel model is proposed based on a central hydrophobic beta-strand region flanked by an N-terminal polar alpha-helix and a C-terminal amphipathic alpha-helix. The possibility that oleosins exhibit structural and functional similarities with some animal apolipoproteins is discussed.

Amino Acid Sequence↗
PubMed1989

Low-resolution epitope characterisation in a family of seed apolipoproteins using polyclonal antibodies.

Polyclonal antibodies raised against a range of seed apolipoproteins from the family Cruciferae have been used for the first time for low resolution epitope characterisation. Antibodies were raised against the major seed apolipoproteins of Brassica napus, Sinapis alba and Raphanus sativum. In each case, the antibodies recognized, in addition to the 19-20 kDa apolipoprotein to which they were raised, similar 19-20 kDa apolipoproteins from a wide range of species in the family Cruciferae, but not in other plant families. Homologous or heterologous two-sites (sandwich) assays were performed with the format [antibody A - test apolipoprotein - antibody B - 2 degrees antibody]. The results showed a drastically reduced antibody B binding by apolipoproteins preincubated with an antibody A. This indicated the presence of a single major epitope on many of the apolipoproteins. The antigenicity of native and denatured apolipoproteins was similar, although the antigenicity of the former was much more readily destroyed by proteinase attack. It is concluded that there are relatively few major epitopes present on the Cruciferae apolipoproteins and it is suggested that these epitopes are localized on the small hydrophilic surface-exposed C- and N-terminal domains of the apolipoproteins.

Antibodies↗
PubMed1989

An immunologically related family of apolipoproteins associated with triacylglycerol storage in the Cruciferae.

The major apolipoproteins associated with oil-storage bodies have been isolated from the mature seeds of six different species of the family Cruciferae. The apolipoproteins were all of molecular mass 19-20 kDa. They were highly abundant in mature seed tissue, accounting for up to 20% total seed proteins, and were localized exclusively on the membranes of oil-storage bodies. Antibodies were raised in rabbits and mice against the six purified apolipoproteins. In each case, the antibodies specifically recognized 19-20 kDa polypeptides on immunoblots of total seed proteins from 15 different species of the Cruciferae. The extent of the immunological cross-reactivity among the six purified seed apolipoproteins of the Cruciferae was investigated quantitatively using enzyme-linked immunosorbent assay. Very high levels of cross-reactivity were obtained, in contrast to a complete lack of cross-reactivity observed when the major seed apolipoprotein of a non-crucifer, Glycine max, was assayed. Peptide mapping studies showed that the different crucifer seed apolipoproteins gave rise to similar proteolytic cleavage products following treatment with Staphylococcus aureus V8 protease, Lysobacter enzymogenes Lys-C endoprotease, and trypsin. The patterns of immunogenic proteolytic cleavage products of the different apolipoproteins were also similar. We propose that there is a family of abundant 19-20 kDa apolipoproteins in mature seeds of oil-bearing Cruciferae. These apolipoproteins are all major components of the membranes of oil-storage bodies. The apolipoproteins are therefore very closely related with respect to their structure, function, and immunological properties.

Antibodies↗