Genetic polymorphism of plasma alpha 1 B-glycoprotein and transferrin in arctic and silver foxes

A previously reported polymorphic plasma protein of dogs and horses, identified as apolipoprotein A-IV

By using immunoblotting with antiserum specific to human plasma apolipoprotein A-IV (apoA-IV), a previously reported polymorphic plasma protein of dogs viz postalbumin-2 (Pa2) and one of horses viz serum protein 2 (SP2), were identified as apoA-IV of these species. This along with earlier published results implied that: (1) both dog and horse show a high degree of polymorphism at the APOA4 locus with three common alleles in each of the two species; and (2) apoA-IV phenotyping in these two species can be done by analysing plasma/serum samples by a simple method of two-dimensional electrophoresis, conducted under non-denaturing conditions, followed by general-protein staining of gels.

Polymorphic plasma postalbumin (Po) of llamas and alpacas identified as Gc protein

Immunoblotting with antiserum specific to human Gc protein was used to identify Gc protein as the previously reported polymorphic plasma postalbumin (Po) of llamas and alpacas. This is the first report of Gc polymorphism in camelid species. One Gc variant appeared to be identical in llamas, alpacas, dromedaries and bactrian camels.

Two-dimensional electrophoresis of the plasma proteins of alpacas and llamas: genetic polymorphism of alpha 1B-glycoprotein and three other proteins

Plasma samples of alpacas and llamas were analysed by a simple method of two-dimensional (2-D) agarose gel (pH 8.6)-horizontal polyacrylamide gel (pH 9.0) electrophoresis, followed by general protein staining of gels. Genetic polymorphism in both species is described for alpha 1B-glycoprotein (alpha 1B) and three other unidentified proteins designated prealbumin (Pr), postalbumin 1 and 2 (Pa1 and Pa2). alpha 1B was identified by cross-reactivity with antisera for human and pig alpha 1B. Altogether, two alleles of Pr, two of Pa1, five of alpha 1B and three of Pa2 are described. Most of the alleles were present in alpacas and llamas. Alpacas showed a high degree of polymorphism at all four loci. Llamas showed considerable polymorphism at only the Pa1 and Pa2 loci. The theoretical probability of exclusion (PE) of an incorrectly assigned parent was estimated to be about 80% in each species by typing for the six polymorphic plasma proteins reported so far in these species. The given method of 2-D electrophoresis revealed no fixed differences in protein mobilities that discriminate between llamas and alpacas.

Three new plasma protein polymorphisms in domestic foxes, detected by a simple method of 2D horizontal electrophoresis

Plasma samples of 270 foxes from 45 complete families (14 of arctic foxes, 28 of silver foxes and 3 with arctic x silver fox hybrid offspring) were analysed by a method of two-dimensional agarose gel (pH 5.4)-horizontal polyacrylamide gel (pH 9.0) electrophoresis followed by general-protein staining of gels. Genetic polymorphism of three plasma proteins, tentatively designated prealbumin (Pr), postalbumin 1 (Pa1), and pretransferin 1 (Prt1), was observed. In silver foxes, Pa1 and Prt1 showed a high degree of polymorphism, each with 3 common alleles, while Pr showed a scarce polymorphism. The arctic foxes were monomorphic for Pr and Prt1 and showed a scarce Pa1 polymorphism. The Prt1 phenotype of arctic foxes showed identical mobility with one of the Prt1 variants of silver foxes.

Mass spectrometry identification of circulating alpha-1-B glycoprotein, increased in aged female C57BL/6 mice

In this study, we surveyed the profiles of mouse circulating proteins by 2-dimensional SDS-PAGE in different strains, sexes and ages. Among visible protein spots on 2-D gels with silver-staining, we identified a unique set of 7 seemingly-related proteins whose levels were consistently elevated in older C57BL/6 female mice. This set of 7 proteins was absent in C57BL/6 males or in BALB/c mice of either sex of any age. When C57BL/6 female mice were crossed with BALB/c males, the age-related increase of these proteins became sporadic and not linear in the F1 offspring. All 7 spots of this protein group were picked and subjected to identification by mass spectrometric analysis after tryptic digestion. The results showed that all 7 spots were different isoforms of alpha(1)B-glycoprotein with different degrees of post-translational modifications, such as phosphorylation. These results suggest that alpha(1)B-glycoprotein changes in mice in a sex and age dependent manner.

Donkey and horse alpha 1 B-glycoprotein: partial characterization and new alleles

1. The donkey postalbumin protein has been shown to be the equivalent of human alpha 1 B-glycoprotein by protein immunoblotting and N-terminal amino acid sequence. 2. The horse A1B system (already identified as the homologue of human alpha 1 B-glycoprotein) and the donkey alpha 1 B-glycoprotein were characterized further for terminal sialic acid content, isoelectric point, amino acid composition and affinity for the dye-ligand, Cibacron Blue F3GA (known to bind human alpha 1 B-glycoprotein). 3. Two new alleles in the horse A1B system were found, bringing the total number of alleles to five. No polymorphism was found in the donkey alpha 1 B system. 4. As expected the first 20 N-terminal residues of the donkey and horse proteins are highly conserved with only two differences being found. 5. The polymorphism of the horse alpha 1 B-glycoproteins may be due in part to differing numbers of terminal sialic acid residues and the higher electrophoretic mobility of the donkey alpha 1 B-glycoprotein may be due in part to increased sialylation. 6. The horse and donkey alpha 1 B-glycoproteins exhibited differences in affinity for the dye-ligand, Cibacron Blue F3GA, with the donkey alpha 1 B-glycoprotein not being bound.