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 α1B-glycoprotein and three other proteins

Summary. 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 α 1 B-glycoprotein (α 1 B) and three other unidentified proteins designated prealbumin (Pr), postalbumin 1 and 2 (Pal and Pa2). α 1 B was identified by cross-reactivity with antisera for human and pig α 1 B. Altogether, two alleles of Pr, two of Pa1, five of α 1 B 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 (P e ) 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.     

Polymorphic post-albumin of cattle and horse plasma identified as vitamin D binding protein (Gc protein)

Cattle and horse plasma samples of known post-albumin types were radiolabelled with ¹⁴C-vitamin D₃. These samples were then analysed by polyacrylamide gel electrophoresis, followed by autoradiography. The patterns observed were identical to those of post-albumin variants. The polymorphic post-albumin protein of cattle and horse was thus identified as the vitamin D binding protein and homologous to the Gc protein of human plasma.     

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

Summary. 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.     

Genetic polymorphism of plasma vitamin D-binding protein (GC) in Australian goats

Polymorphism at the GC locus in goats was detected using isoelectric focusing (pH 4.5-5.4) and immunoblotting with antiserum to human GC. Three variants, designated A, B and C in order of decreasing mobility to the anode, were detected and were shown to be controlled by three codominant alleles, GCA, GCB and GCC. GCA and GCB occurred in all four breeds (Australian and Texan Angora, Cashmere and Dairy) with GCA being the most common and having gene frequencies ranging from 0.851 to 0.993. GCC was found only in Australian Angora and Cashmere animals. The products of the three GC alleles had isoelectric points in the range pH 4.63-4.95 and M(r) of approximately 54,375. The major isoforms of the three alleles were shown to contain sialic acid. Linkage between the GC and albumin loci was unable to be demonstrated due to the low frequency of ALBA (0.02) in the Cashmere breed.     

Polymorphic plasma postalbumins of some domestic animals (pig PO2, horse Xk and dog Pa proteins) identified as homologous to human plasma α1B-glycoprotein

Pig, horse and dog plasma proteins, separated by horizontal polyacrylamide gel electrophoresis (pH 9.0) and electrophoretically transferred to nitrocellulose membranes, were tested for cross-reaction with antiserum to human plasma alpha 1B-glycoprotein (alpha 1B). The results showed that one previously reported polymorphic plasma postalbumin in each of these species (pig PO2, horse Xk and dog Pa protein) was homologous to human plasma alpha 1B. In the light of the previously known genetic linkages in these species, this implied: (1) alpha 1B gene is close linked to Phi, Pgd and Hal (halothane sensitivity locus) loci in pigs; and (2) alpha 1B gene is linked to ME1 and Phi loci in horses. This suggested that the alpha 1B gene may also be found to be closely linked to gene(s) controlling susceptibility to malignant hyperthermia in humans and other mammals.     

Genetic polymorphism of serum vitamin D-binding protein (GC) in sheep and mouflon

One-dimensional polyacrylamide gel electrophoresis (1D PAGE) followed by immunoblotting revealed genetic polymorphism of GC protein in sheep (variants F, S, V) and mouflon (variants F and S, apparently identical to F and S of sheep). The frequency of Gcs allele ranged from 0.84 to 1.0 in the 12 breeds of sheep studied. GcV allele was observed only in Tsigai breed with a frequency of 0.017.     

A previously described serum protein polymorphism in the rat identified as Gc ('vitamin D-binding protein')

The previously published serum protein polymorphisms Gl-1 (Moutier, Toyama & Charrier, 1973) and tf (Bender & Gunther, 1978) are identical and represent genetic variation at the locus of the vitamin D-binding arglobulin, also known as Gc or group-specific component. The identity was established by comparative protein staining, by functional tests with ^;4C-vitamin D₃, by immunological studies with specific anti-Gc sera and by the strain distribution patterns. The Gc polymorphism in the rat may initiate interesting physiological and genetical studies.     

Genetic polymorphism of the vitamin D binding protein (Gc) in the musk shrew (Suncus murinus)

In the musk shrew ( Suncus murinus ), the electrophoretic bands in the post-albumin region were identified as vitamin D binding protein (Gc) by the [³HI vitamin D₃ binding method. Three Gc phenotypes were distinguished from each other: a single faster band (Gc-A), a single slower band (Gc-B) and the double bands (Gc-AB). Results of mating experiments indicated that the Gc-A and Gc-B are controlled by two codominant alleles, Cc ^a and Gc ^b at an autosomal locus ( Cc ), respectively. It was noticed that, in the Gc-AB phenotypes, the Gc-B band was constantly more intense than the Gc-A band in the protein staining. The same tendency was also observed btween the homozygous Gc-A and Gc-B bands, and further, radioactivity of the Gc-B bound with [³H] vitamin D₃ was about twofold higher than that of the Gc-A. These results suggest that the Gc^b yields its protein product twofold more than the Gc ^a. No cross-reaction between the shrew proteins and a rabbit anti-human Gc protein was observed.     

Preliminary report on two new plasma protein polymorphisms in the goose (Anser anser)

Two-dimensional agarose gel (pH 8.6)-horizontal poly acrylamide gel (pH 9.0) electrophoresis of plasma proteins in the goose was done. This method resulted in improved separation of proteins in the pre-transferrin and transferrin regions. Preliminary evidence was presented for the existence of two new plasma protein poly morphisrns.     

Genetic polymorphism of the vitamin D binding protein (Gc protein) in pig plasma determined by agarose isoelectrofocusing

Genetic polymorphism of the pig plasma vitamin D binding protein Gc was demonstrated by agarose isoelectrofocusing followed by either autoradiography or immunofixation with specific human Gc antiserum. Three different types F, FS and S were observed. Family data supported the genetic theory that the Gc types are controlled by two autosomal codominant alleles Gc^F and Gc^s . Both alleles are present in Yorkshire and Duroc. In Danish Landrace and Hampshire only the Gc^F allele was observed.     

Genetic variation at pig plasma protein locus PLP1 and its assignment to chromosome 5

A new genetic polymorphism of an unidentified plasma protein (PLP1) in pigs was described by using a method of two-dimensional gel electrophoresis and protein staining. Two codominant alleles, with frequencies of 0.83 and 0.17, were found in the Swedish Yorkshire breed. The PLP1 marker was typed in a three-generation pedigree and tested for linkage against a set of 128 markers. The PLP1 locus showed significant LOD score values with three different microsatellite markers (S0092, DAGK and S005), previously assigned to chromosome 5.     

Blood protein polymorphisms in the donkey (Equus asinus)

Transferrin, albumin, 6-phosphogluconate dehydrogenase and vitamin D-binding protein polymorphisms were detected in 242 feral and domesticated Australian donkeys by polyacrylamide gel electrophoresis, starch gel electrophoresis, autoradiography, immunoblotting with specific antisera and activity staining. All four TF and two ALB variants were donkey specific while only one of the PGD variants was donkey specific. The two GC variants were electrophoretically identical to the Equus caballus F and S proteins. Available evidence suggested that the TF, ALB, PGD and GC systems are controlled by co-dominant alleles with frequencies of the most common alleles of each system being 0·831, 0·946, 0·957 and 0·861 respectively. Glucose phosphate isomerase and plasminogen were monomorphic in the Australian population of donkeys.     

Genetic polymorphism of plasma α1B-glycoprotein and transferrin in arctic and silver foxes

Plasma samples of 235 foxes from 38 complete families (14 of arctic foxes, 21 of silver foxes and 3 with arctic x silver fox hybrid offspring) were analysed by one-dimensional horizontal polyacrylamide gel electrophoresis (PAGE) pH 9.0 followed by general-protein staining of gels. A major postalbumin of fox plasma was identified as alpha 1B-glycoprotein (alpha 1B) by using immunoblotting with antiser m specific to human or pig plasma alpha 1B. Four codominant, autosomal alleles of alpha 1B were found in arctic foxes. Two transferrin (TF) alleles (TfF, TfS) were observed in arctic foxes and two (TfD, Tff) in silver foxes; the TF F type of both of the fox species showed identical electrophoretic mobilities. The arctic foxes showed a high degree of polymorphism for both TF and alpha 1B. The silver foxes showed a scarce polymorphism of TF and were monomorphic for alpha 1B. The arctic fox, silver fox and their hybrids could be clearly differentiated from one another by their plasma protein patterns obtained by the PAGE method.     

Polymorphic serum prealbumin (Pa) of pig, identified as an a!-protease inhibitor

Pig serum proteins were analysed by horizontal polyacrylamide gel electrophoresis, with a discontinuous buffer system (pH 9.0). A 12 % acrylamide concentration in the separation gel was used. Each of the two prealbumin (Pa) alleles gave rise to two closely migrating fractions. The polymorhic Pa was identified as an a,-protease inhibitor as the Pa fractions inhibited the esterolytic activity of both bovine trypsin and chymotrypsin. Therefore, it has been proposed that the locus symbol for this prealbumin be changed to Pi-1. The protease inhibitory spectra and electrophoretic mobility of the Pa (Pi-1) fractions suggested that this protein was probably the same as the pig serum a,-protease inhibitor described in some earlier studies and that it corresponds to human serum a,-protease inhibitor (Pi).     

Genetic polymorphism and close linkage of two plasma protein loci in dogs

By using a simple method of two-dimensional horizontal electrophoresis, phenotypes of an unidentified plasma protein (PA4) were determined in 967 dogs belonging to 43 different breeds. Two codominant, autosomal alleles (F and S) of PA4 were reported. While many of the breeds of middle and north-eastern Asia (akita inu, Alaskan malamute, chow chow, samoyed, Siberian husky and Tibetan terrier) showed a substantial frequency (0.1 to 0.6) of the S allele, a majority of the European breeds had only the F allele. Evidence was provided that the PA4 locus is closely linked to the plasma pretransferrin 1 locus (PRT1). No recombinant was observed in 45 informative offspring studied. In nearly all breeds, the PA4 S allele was almost always in coupling phase with the PRT1 F allele.     

Different structural stability and toxicity of PrP(ARR) and PrP(ARQ) sheep prion protein variants

The polymorphisms at amino acid residues 136, 154, and 171 in ovine prion protein (PrP) have been associated with different susceptibility to scrapie: animals expressing PrP^ARQ [PrP(Ala136/Arg154/Gln171)] show vulnerability, whereas those that express PrP^ARR [PrP(Ala136/Arg154/Arg171)] are resistant to scrapie. The aim of this study was to evaluate the in vitro toxic effects of PrP^ARR and PrP^ARQ variants in relation with their structural characteristics. We show that both peptides cause cell death inducing apoptosis but, unexpectedly, the scrapie resistant PrP^ARR form was more toxic than the scrapie susceptible PrP^ARQ variant. Moreover, the α-helical conformation of PrP^ARR was less stable than that of PrP^ARQ and the structural determinants responsible of these different conformational stabilities were characterized by spectroscopic analysis. We observed that PrP toxicity was inversely related to protein structural stability, being the unfolded conformation more toxic than the native one. However, the PrP^ARQ variant displays a higher propensity to form large aggregates than PrP^ARR. Interestingly, in the presence of small amounts of PrP^ARR, PrP^ARQ aggregability was reduced to levels similar to that of PrP^ARR. Thus, in contrast to PrP^ARR toxicity, scrapie transmissibility seems to reside in the more stable conformation of PrP^ARQ that allows the formation of large amyloid fibrils.     

Genetics of four plasma protein loci in Equus przewalskii: new alleles at the prealbumin, postalbumin and transferrin loci

This paper reports genetic variation at the prealbumin ( Pr ), postalbumin ( Pa ) and transferrin ( Tf ) loci in Equus przewalskii found using thin layer isoelectric focusing and an amphoteric separator. The method resolves all three loci plus serum esterase ( Es ) on a single gel, and typing of all four loci is readily achieved. In addition to the esterase alleles previously reported by Fisher & Scott (1979), five alleles were found at the Pr locus. three at the Pa locus and six at the Tf locus. Analysis of several mating types confirms inheritance is autosomal and codominant for all four loci.     

Genetic polymorphism of the sixth component of complement (C6) in the pig

Summary
Using agarose gel isoelectric focusing and immunoblotting with rabbit anti-rabbit C6, a genetic polymorphism has been found in the sixth component of complement (C6) in six breeds of pigs. The C6 locus was highly polymorphic. Family data indicated that pig C6 pheno-types were inherited by means of five codomonant alleles named C6 ^A, C6 ^B, C6 ^C, C6 ^D and C6 ^E at a single autosomal locus. C6 deficiency in two of 241 individuals tested was found, which suggested the presence of a null allele in pig populations. Marked breed differences among the gene frequencies and heterozygosities at C6 locus were observed.     

Parentage testing of dogs using variants of blood proteins: description of five new plasma protein polymorphisms

Plasma samples of 1126 dogs belonging to 21 different European breeds were analysed by two-dimensional agarose gel (pH 5.4 or pH 8.6)--horizontal polyacrylamide gel (pH 9.0) electrophoresis, followed by general-protein staining of gels. Genetic polymorphism was detected for five as yet unidentified proteins designated pretransferrin-1 and -2 (Prt1 and Prt2) and postalbumin-1, -2 and -3 (Pa1, Pa2 and Pa3). Three alleles are reported in the Prt1 and Prt2 systems and two alleles in the Prt2, Pa1 and Pa3 systems. While Prt2 variation was observed only in the cocker spaniel breed, each of the other four proteins showed a high degree of polymorphism in most of the breeds studied. Pa3 fractions were clearly observed only in samples stored at -20 degrees C for more than 2 years. Prt1, Pa1 and Pa2 proteins are additional useful markers for parentage control in dogs. This study corroborated previously published results that dog plasma proteins, in general, show considerably more polymorphism than that reported for haemoglobin and for several blood cell enzymes in this species.