Quantitation of hemoglobin alpha chains in adult and fetal goats; gene duplication and the production of polypeptide chains

Differential expression of I alpha- and II alpha-globin genes in Norwegian dairy goats

Fast protein liquid chromatography (FPLC) and polyacrylamide gel electrophoresis were used to determine the ratio between I alpha- and II alpha-globin chains in Norwegian dairy goats. Three different phenotypes, designated normal (N) with I alpha- to II alpha-globin ratio 3:1, reversed (R) with ratio 1:2 and double-reversed (RR) with no I alpha-globin, were described. Family studies indicated that the R animals were heterozygous, and the RR animal homozygous, for a haplotype without a functional I alpha-globin product. Southern blot analysis of goat DNAs digested with six different restriction enzymes showed that the different ratios of alpha chain expression could not be due to a deletion of the I alpha-gene and/or duplication or triplication of the II alpha-globin genes. The homozygous reversed animal with no detectable I alpha-globin had a mild anaemia.

Expression and genetics of caprine haemoglobins

The expression of haemoglobin (Hb) has been studied in 260 Norwegian Dairy goats by the Immobiline technique at pH ranges 6.7-7.7, 6.9-7.6 and 6.9-7.5. The majority of goats exhibited two- or four-band patterns. In two-band types the average ratio between the anodal and cathodal band was 74:26. PAGE with 8M urea distinguished three phenotypes for the beta chains, proving that the Hb variation described is in the beta chain. Segregation data in 106 complete sire-dam-offspring families agreed with the existence of four beta globin alleles--A2, A4, A6 and A8. Twenty-seven animals had reversed ratios (R) of Hb bands. In two-band phenotypes the average ratio was 36:64. In 15 complete families where one of the parents had reversed ratio, eight offspring received the R type, indicating a simple genetic control. After urea PAGE the R animals all showed the same alpha chain phenotype which differed from that of goats having common ratios of bands. An additional polymorphism appeared in nine animals as three- and five-band patterns which is assumed to be the result of heterozygosity for II alpha and for II alpha and beta globin genes respectively.

An investigation of five genetic loci controlling polymorphic variants in the red cells of goats

Results of a joint study carried out in South Africa and England to search for new genetic markers in the blood of goats are presented. Haemoglobin (Hb) phenotypes were reinvestigated with the technique of isoelectric focusing; frequencies in different goat breeds are given. Anaemic Hb type A, AB and B goats all produced a Hb C with an identical electrophoretic pattern. All goats tested had identical carbonic anhydrase (CA) types, but showed polymorphism of 'X' protein. Preliminary results indicated that nucleoside phosphorylase (NP) may be polymorphic.

The sequence and phylogenesis of the ?-globin genes of Barbary sheep (Ammotragus lervia), goat (Capra hircus), European mouflon (Ovis aries musimon) and Cyprus mouflon (Ovis aries ophion)

In order to investigate the polymorphism of ?-globin chain of hemoglobin amongst caprines, the linked (I)? and (II)? globin genes of Barbary sheep (Ammotragus lervia), goat (Capra hircus), European mouflon (Ovis aries musimon), and Cyprus mouflon (Ovis aries ophion) were completely sequenced, including the 5? and 3? untranslated regions. European and Cyprus mouflons, which do not show polymorphic ? globin chains, had almost identical ? globin genes, whereas Barbary sheep exhibit two different chains encoded by two nonallelic genes. Four different ? genes were observed and sequenced in goat, validating previous observations of the existence of allelic and nonallelic polymorphism. As in other vertebrates, interchromosomal gene conversion appears to be responsible for such polymorphism. Evaluation of nucleotide sequences at the level of molecular evolution of the (I)?-globin gene family in the caprine taxa suggests a closer relationship between the genus Ammotragus and Capra. Molecular clock estimates suggest sheep-mouflon, goat-aoudad, and ancestor-caprine divergences of 2.8, 5.7, and 7.1 MYBP, respectively.

Bovine hemoglobin alpha-globin chain polymorphism: primary structure determination of two new genetic variants by mass spectrometry and amino acid sequencing

The present work describes the biochemical procedures used to identify the cause of a quantitative and qualitative hemoglobin polymorphism found in Podolian cattle. First, to analyze the different phenotypes, isoelectric focusing (IEF) of hemoglobins and RP-HPLC of globin chains was carried out; secondly, to determine accurately the globin molecular masses, electrospray mass spectrometry was performed and finally to check the entire amino acid sequences of the proteins, several enzymatic digests were analyzed by fast atom bombardment mass spectrometry (FAB-MS) and Edman degradation procedure. As to the qualitative polymorphism, the results of RP-HPLC show the presence of two alpha-globin variants to which the extensive mass spectrometric analysis attributed a molecular mass of 15,026.47 +/- 0.44 Da and 15,079.86 +/- 0.66 Da and whose respective primary structure differed from that of the common alpha-globin chain in the amino acid substitution Asn-->Ser at position 131 and the other in the replacement of the histidine residue at position 89 with tyrosine. As to the quantitative polymorphism, on the basis of the expression gradient found out in the duplicated alpha genes of several mammals, we conceive that the alpha 89 His-->Tyr is an allelic form of the I alpha gene while the alpha 131Asn-->Ser is an allelic form of the II alpha gene.

Changes in alpha-globin gene expression in mice of two alpha-globin haplotypes during development

Adult alpha-globin in mice is synthesized in large amounts during development, first in the primitive, nucleated erythrocytes of yolk sac origin and later in the definitive, nonnucleated erythrocytes that differentiate in the fetal liver, spleen, and bone marrow. Isoelectric focusing analysis of hemoglobins of mice with the Hbag2 and Hbac haplotypes shows that the ratios of alpha chain 1 to chain 5m and alpha chain 1 to chain 4 in adult hemoglobins from Hbag2 and Hbac mice, respectively, change between day 11.5 and day 16.5 of gestation in nucleated red cells, while no change occurs in nonnucleated red cells. The percentage ratios of the two different alpha-globin chains are different in Hbag2 and Hbac mice for EII, EIII, and adult hemoglobin. In nucleated red cells of yolk sac origin, differences and changes in alpha-globin ratios are a composite of changing globin gene transcription and posttranslational competitive affinities among globins to form embryonic and adult hemoglobin tetramers.

Hemoglobin types in Saanen goats and Barbary sheep: genetic and comparative aspects

By the use of the Immobiline technique at pH ranges 7.0-7.6 and 6.9-7.9, 16 different hemoglobin (Hb) phenotypes were observed in 61 English Saanen goats. They are explained in this breed by a genetic theory of five beta-globin genes (A4, A6, A8, E, and D) and two closely linked alpha-globin loci ('alpha and "alpha) of which the "alpha has a variant allele, provisionally called "alpha X. Family data together with observed and expected Hb frequencies were in agreement with the genetic theory. Among six Barbary sheep there were three Hb phenotypes explained by the occurrence of the beta-chain alleles B and Cna.

High performance liquid chromatographic separation of the globin chains of non-human hemoglobins

High performance liquid chromatography has been applied to the separation of the globin chains of 16 non-human species which include common mammalian and avian species. The procedure uses a large-pore C4 column which has been effectively employed for the separation of human globin chains. In many cases, the gradient for human chains with trifluoroacetic acid-water-acetonitrile was satisfactory or required only moderate modification. The separations were excellent for all except dog hemoglobin. Many results substantiate prior published information about heterogeneity, amino acid composition, etc. of the individual hemoglobins. Additional data on some of these hemoglobins have also been obtained, and some previously unstudied hemoglobins have been examined.

Synthesis of hemoglobin chains in adult and newborn goats: possible influence of the beta c synthesis on the production of alpha chains

The rates of in vitro synthesis of hemoglobin alpha and non-alpha chains were determined in adult goats during blood loss anemia and in newborn goats during postnatal development. The reticulocytes were incubated in a medium supporting protein synthesis and containing [14C] leucine. The hemoglobin chains were separated by CM-cellulose chromatography. The adult animals responded to the phlebotomy with a production of nearly 100% beta C chain about 10 days after the start of the experiment. Severe anemia and the production of beta C chain was accompanied by a significant increase in the alpha/non-alpha synthesis ratio. The gamma chain production in the newborns declined rapidly after birth and was completely replaced by that of the beta C chain in 7-10 days. No significant difference in the relative synthesis of the three types of alpha chain was observed during this period. Goats with either a homozygosity for the I alpha or I alpha B chains synthesize the I alpha (or I alpha B) and II alpha chains at a ratio of 3:1. When a heterozygosity for I alpha B chains is present the I alpha:I alpha B:II alpha ratio approximates 2:1:1. Results of kinetic studies suggest that the II alpha chains are synthesized at a slower rate than the II alpha chains. The difference in the alpha/non-alpha ratio during severe anemia may be due to a decreased production of beta C chains. No significant difference in the relative synthesis of the I alpha, I alpha B, and II alpha chains was observed between the anemic adult animal and the newborn goat or the growing kid.

The structure of goat hemoglobins. V. A fourth beta chain variant (beta-D-Malta; 69 Asp is replaced by Gly) with decreased oxygen affinity and occurring at a high frequency in Malta

During a survey of hemoglobin types in goats in the Republic of Malta a variant (Goat Hb D-Malta) was discovered which differs from normal goat Hb A by the substitution of an aspartyl residue in position beta 69 (E13) by a glycyl residue. The gene frequency of the beta D allele was 0.255; 29 homozygous Hb D goats were present among 327 animals sampled. Homozygous Hb D goats also produce Hb C, whose beta chains are the product of a non-allelic beta C structural gene. Goat Hb D-Malta has a distinctly decreased affinity for molecular oxygen.

Hemoglobin ontogenesis: test of the gene excision hypothesis

The gene excision hypothesis of hemoglobin ontogenesis was tested in persons with HbSC disease, with the use of monospecific fluorescent antibodies for the identification of hemoglobins S, C, and F in individual erythrocytes. The results are incompatible with the prediction that only one gamma- or beta-globin gene may be active in any single chromosome and provide further evidence for incomplete repression of gamma-globin genes lying cis to active beta-globin genes.

Multiple hemoglobin alpha-chains in the sika deer (Cervus nippon)

Investigation of the hemoglobin alpha-chains of an Asiatic deer, the sika (Cervus nippon), was prompted by the heterogenity of alpha-chain gene loci in the Virginia white-tailed deer (Odocoileus virginianus). Although electrophoresis of hemoglobin chains from 10 sika revealed only a single alpha-chain band, peptide mapping demonstrated variations in the alpha-TPIII and alpha-TPIV peptides. Substitutions at positions 15, 20, and 22 produced a minimum of five alpha-chains; two possible additional chains could noy be proven because of inseparability of the whole alpha-chains. The most common chain contains Asp-15, Lys-20 and Pro-22 but in other chains glycine is present at position 15, Asx at position 20, and either serine or Asx at position 22. The probable explanation for the large number of alpha-chains is gene duplication which may have been produced by breedings between subspecies from different geographical areas. Comparison with the alpha-chain structure of the white-tailed deer suggests that the sika may have evolved from the lineage which produced the white tailed-deer after the alpha-chain genes of the latter species had duplicated. In addition, these data provide further examples of the unusual variability of this portion of the alpha-chain.

Primary sequence of the beta-chain of Badger haemoglobin

Badger (Meles meles) haemoglobin was purified by paper electrophoresis and converted into globin. Chain separation was carried out on a CM-cellulose column in the presence of 8 M urea. The beta-chain was aminoethylated, purified by gel filtration and submitted to tryptic digestion. A fingerprint obtained with the enzymic digests showed 17 distinct ninhydrin-positive spots from which 20 pure peptides were isolated by further electrochromatographic separations. These peptides were sequenced using Dansyl-Edman and Ptc-Edman degradation techniques. The presence of amide residues was confirmed after aminopeptidase M hydrolysis. Taking human haemoglobin beta-chain as a model, the covalent structure could be completely resolved without the help of any further overlapping technique. The following substitutions were noted (badger/human, position): Ala/Pro5, Ser/Ala13, Tyr/Phe41, Asp/Glu43, Ser/Ala70, Glu/Asp73, Lys/Ala76, Asn/His77, Lys/Thr87, Lys/Arg104 and Gln/Pro125. A comparison with other haemoglobin beta-chains already sequenced shows a greater similarity with dog haemoglobin, the only example of beta-chain of known structure in the order of Carnivores.

The erythroid cells and haemoglobins of the chick embryo

The changes in the types of erythroid cells produced during embryogenesis of the chick have been correlated with the changes in the types of haemoglobins found in the embryo. Primitive erythroid cells constitute the only red blood cells of 2- to 5-day embryos. The first recognizable immature definitive erythroid cells appear in the embryonic circulation at 5 to 6 days and progressively replace the primitive cells, such that by 14 to 16 days the primitive cells constitute less than 1 % of the circulating erythroid cells. Primitive erythropoiesis is strikingly different from definitive erythropoiesis. At any one time point between 2 and 16 days, all of the isolated primitive cells appear, by morphological criteria, to be at the same stage of maturation, and, although variation in cell size is observed, for an individual maturation stage, the small cells are not more mature than the medium-size cells, nor are the large cells less mature than the medium or small cells. Maturing primitive erythroid cells undergo the progressive changes in cell structure characteristic of erythroid maturation in mammalian erythropoietic systems, but do so as a uniform cell population. Haemoglobin, isolated from primitive erythroid cells of 2- to 5-day embryos, shows two components on polyacrylamide gel electrophoresis, haemoglobin E and haemoglobin P. The haemoglobin E/P ratio is constant in lysates from 2- to 5-day embryos. A t 6 to 7 days when the first haemoglobinized immature definitive erythroid cells appear in the embryonic circulation, two new haemoglobin components are observed in lysates of erythroid cells. These two new haemoglobin components are electrophoretically and immunologically identical to the two haemoglobin components of adult chickens, haemoglobins A and D. As the definitive erythroid cells replace the primitive erythrocytes in the embryonic circulation, the haemoglobins A and D increase in amount and replace haemoglobin P. Haemoglobin P cannot be detected immunologically in erythroid cell lysates from 16-day embryos which contain less than 1 % primitive cells. In erythroid cell lysates from late embryos, which contained few, if any, primitive erythrocytes, a minor haemoglobin, electrophoretically similar to haemoglobin E on pH 10.3 polyacrylamide gels, is consistently observed. This component differs from haemoglobin E on pH 8.9 polyacrylmide gels, on Sephadex G-100 columns, on polyacrylamide gels of different porosities, and shows a reaction of only partial identity with haemoglobin E by two-dimensional immunodiffusion. This haemoglobin component, haemoglobin H, is detectable electrophoretically in lysates from 12-day embryos and immunologically in lysates from 8-day embryos. Haemoglobin H has not been observed in adult chickens. The switch from the production of primitive to definitive erythroid cells during development of the chick embryo is associated with the initiation of synthesis of three new haemoglobins, the two adult haemoglobins and haemoglobin H. The haemoglobin D /A ratio of adult chicken haemoglobin, determined from the ratio of gel scan peak masses, is 0.30. When haemoglobins D and A first appear in erythroid cell lysates from 6- to 7-day embryos, the haemoglobin D /A ratio is about 0.9. T he D/A ratio of lysates falls to 0.5 by 16 to 18 days, a time when 99 % of the erythroid cells of the embryo are mature definitive erythrocytes. However, the haemoglobin D /A ratio of lysates from late embryos and young chicks of 0.5 to 20 days of age is consistently greater than that of adult chicken haemoglobin. Definitive erythrocytes of chick embryos and young chicks appear to differ from definitive cells of adult chickens in at least two ways: the presence of haemoglobin H and the higher haemoglobin D/A ratio.

Hemogloblin switching in sheep and goats: erythropoietin-dependent synthesis of hemoglobin C in goat bone-marrow cultures

The anemia-induced switch from hemoglobin A (alpha(2)beta(2) (A)) to hemoglobin C (alpha(2)beta(2) (C)) synthesis occurring in vivo in sheep and goats has been reproduced in tissue culture of goat bone-marrow cells. Cultivation of primary cultures of goat bone marrow in the presence of erythropoietin results in the appearance of detectable amounts of beta(C) globin after 48-72 hr, as well as in a decrease in beta(A) globin. A population of proerythroblasts, as well as active heme and globin synthesis, are maintained for at least 3 days in erythropoietin-treated, but not in erythropoietin-deficient, cultures. These findings demonstrate (i) maintenance of erythropoietin-responsive cells from bone marrow in vitro, and (ii) switching in vitro from the synthesis of a globin chain coded by one gene to that coded by a different, nonallelic gene. Bone-marrow culture might be a useful model system for study of the mechanism of action of erythropoietin and for study of the activation (and inactivation) of specific genes in vitro.

Nature of fetal hemoglobin in the Greek type of hereditary persistence of fetal hemoglobin with and without concurrent beta-thalassemia

The fetal hemoglobin in the affected members of three Greek families with the hereditary persistence of fetal hemoglobin has only gamma-chains of the type with alanine in position 136. Although certain Negro families had been considered to have only this type of gamma-chains in their fetal hemoglobin, further studies required that they be reclassified. Consequently, the Greek cases are the sole examples of this class among the heterozygotes for the hereditary persistence of fetal hemoglobin. In Greek double heterozygotes for beta-thalassemia and the hereditary persistence of fetal hemoglobin, fetal hemoglobin is increased above the level of hemoglobin F in simple heterozygotes and gamma-chains with glycine in position 136 become apparent. In these individuals, gamma-chains with alanine in position 136 apparently derive from the chromosome for the hereditary persistence of fetal hemoglobin and are present in the hemoglobin F with gamma-chains of both types from the chromosome for beta-thalassemia. When these data are correlated with earlier knowledge of the genetic state of the Greek individuals, modifications of our previous ideas about deletions as the genetic basis of the hereditary persistence of fetal hemoglobin must be considered.