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Characterization of the three HERV-H proviruses with an open envelope reading frame encompassing the immunosuppressive domain and evolutionary history in primates.

The HERV-H family is one of the largest human endogenous retrovirus families, with approximately 1000 elements. Using a direct coupled in vitro transcription/translation approach (PTT for protein truncation test) and an extended series of primers on human genomic DNA, on monochromosomal hybrids and on a BAC library, we could demonstrate that there are only three envelopes with a large open reading frame encompassing the immunosuppressive (ISU) domain, corresponding to 62-, 60-, and 59-kDa potential translational products. The associated proviruses, HERV-H/env62, HERV-H/env60, and HERV-H/env59 were sequenced together with their flanking DNA and mapped by FISH, and their entry times within the primate lineage were determined. Analysis of the LTR sequences revealed numerous recombinational and/or homogenization events in the course of evolution, with divergences between 5' and 3' LTRs higher than expected for a simple time-dependent genetic drift. PTT analyses further revealed that the three large envelopes in humans are prematurely stopped in the majority of primates, and sequencing of the largest envelope gene, from HERV-H/env62, in five human individuals revealed two polymorphic sites. The results are consistent with the absence of a strong selective pressure for the conservation of a functional envelope gene of possible benefit for the host, but do not exclude somatic effects possibly associated with the immunosuppressive domain carried by these genes.

Animals↗

In vitro interaction of coronaviruses with primate and human brain microvascular endothelial cells.

Primary human and primate brain microvascular endothelial cells were tested for permissiveness to coronaviruses JHM and 229E. While sub-genomic viral RNAs could be detected up to 72 hours post-infection, primate cells were abortively infected and neither virus caused cytopathology. Human cells were non-permissive for JHM but permissive for 229E replication; peak production of progeny 229E and observable cytopathic effects occurred approximately 22 and 32 hour post-infection, respectively. Using the criterion of cytopathology induction in infected endothelial cells, 229E was compared to other human RNA and DNA viruses. In addition, virus induced modulation of intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1) and HLA I was monitored by immunostaining of infected cells.

Animals↗

Nonhuman primate herpesviruses: importance for xenotransplantation.

Herpesviruses are found throughout the animal kingdom. Members of this family share properties including a highly orchestrated system of transcription, destruction of the host cell by active viral replication and an ability to persist in the host in a latent form. Human herpesviruses have all been implicated in causing substantial disease after allotransplantation. Often transmission of these viruses has been through the donor organ or blood products. Analogous species of herpesviruses exist in nonhuman primates. Accordingly, concern regarding the risk of their transmission and disease exists with xenotransplant procedures. This chapter reviews herpesviruses of nonhuman primates and their potential implication for causing disease after xenotransplantation.

Animals↗

The major histocompatibility complex of primates.

The major histocompatibility complex (MHC) encodes cell surface glycoproteins that function in self-nonself recognition and in allograft rejection. Among primates, the MHC has been well defined only in the human; in the chimpanzee and in two species of macaque monkeys the MHC is less well characterized. Serologic, biochemical and genetic evidence indicates that the basic organization of the MHC linkage group has been phylogenetically conserved. However, the number of genes and their linear relationship on the chromosomes differ between species. Class I MHC loci encode molecules that are the most polymorphic genes known. These molecules are ubiquitous in their tissue distribution and typically are recognized together with nominal antigens by cytotoxic lymphocytes. Class II MHC loci constitute a smaller family of serotypes serving as restricting elements for regulatory T lymphocytes. The distribution of class II antigens is limited mainly to cell types serving immune functions, and their expression is subject to up and down modulation. Class III loci code for components C2, C4 and Factor B (Bf) of the complement system. Interspecies differences in the extent of polymorphism occur, but the significance of this finding in relation to fitness and natural selection is unclear. Detailed information on the structure and regulation of MHC gene expression will be required to understand fully the biologic role of the MHC and the evolutionary relationships between species. Meanwhile, MHC testing has numerous applications to biomedical research, especially in preclinical tissue and organ transplantation studies, the study of disease mechanisms, parentage determination and breeding colony management. In this review, the current status of MHC definition in nonhuman primates will be summarized. Special emphasis is placed on the CyLA system of M. fascicularis which is a major focus in our laboratory. A highly polymorphic cynomolgus MHC has been partially characterized and consists of at least 14 A locus, 11 B locus, 7 C locus class I allelic specificities, 9 Ia-like class II antigens and 6 Bf (class III) variants.

Animals↗

DNA markers in primate models of human disease.

Nonhuman primates are particularly useful as animal models for common human diseases in which both genetic and environmental factors play important roles. The recent development of DNA markers (restriction fragment length polymorphisms, RFLPs) greatly increases the power of linkage analysis to detect major genes that affect quantitative phenotypes, including those related to diseases. This paper summarizes a strategy for using RFLPs in linkage analysis of baboon pedigrees to identify genes that control lipoprotein phenotype, which in turn is predictive of susceptibility to atherosclerosis. This strategy also can be applied to other common human diseases for which nonhuman primate models exist.

Animals↗

Presence and abundance of CENP-B box sequences in great ape subsets of primate-specific alpha-satellite DNA.

CENP-B, a highly conserved centromere-associated protein, binds to alpha-satellite DNA, the centromeric satellite of primate chromosomes, at a 17-bp sequence, the CENP-B box. By fluorescence in situ hybridization (FISH) with an oligomer specific for the CENP-B box sequence, we have demonstrated the abundance of CENP-B boxes on all chromosomes (except the Y) of humans, chimpanzee, pygmy chimpanzee, gorilla, and orangutan. This sequence motif was not detected in the genomes of other primates, including gibbons, Old and New World monkeys, and prosimians. Our results indicate that the CENP-B box containing subtype of alpha-satellite DNA may have emerged recently in the evolution of the large-bodied hominoids, after divergence of the phylogenetic lines leading to gibbons and apes; the box is thus on the order of 15-25 million years of age. The rapid process of dispersal and fixation of the CENP-B box sequence throughout the human and great ape genomes is thought to be a consequence of concerted evolution of alpha-satellite subsets on both homologous and nonhomologous chromosomes.

Animals↗

Simple repetitive DNA sequences from primates: compilation and analysis.

Simple repeats composed of tandemly repeated units 1-6 nucleotides (nt) long have been extracted from a selected set of primate genomic DNA sequences. Of the 501 theoretically possible, different types of repeats only 67 were present in the analyzed database in at least two different size ranges over 12 nt. They include all simple repeats known to be polymorphic in the primate genome. A list of moderately expanding and nonexpanding oligonucleotide patterns has also been included. Furthermore, we have compiled statistical data with emphasis on the overall variability of the most abundant 67 types of repeats. We have demonstrated that the expandability of at least some simple repeats may be affected by the overall base composition and by flanking sequences. In particular, the occurrence of tandemly repeated CAG and GCC triplets in exons positively correlates with their G+C content. We also noted that in the vicinity of Alu sequences tetrameric repeats are more abundant than in the total genomic DNA. This paper can be used as a comprehensive guide in identification of the most abundant and potentially polymorphic simple repeats. It is also of broader significance as a step toward understanding the contribution of flanking sequences and the overall sequence composition to variability of simple repeats.

Animals↗

Rates of amino acid change in the envelope protein correlate with pathogenicity of primate lentiviruses.

A spectrum of pathogenicity has been observed for primate lentiviruses in their natural hosts. For example, human immunodeficiency virus type 1 (HIV-1) is a potent etiologic agent for AIDS in man, whereas there is no evidence to date which indicates that simian immunodeficiency virus from African green monkeys (SIVAGM) causes immunodeficiency in AGM. We measured the relative rates of amino acid change, as the ratio of the number of nonsynonymous to synonymous (silent) nucleotide substitutions, for six primate lentiviruses evolving in their respective hosts. These rates for the external envelope glycoprotein (gp120) and gag coding sequences are 2-3 times higher for pathogenic HIV-1 and SIVmac (macaque) than for minimally pathogenic SIVAGM and SIVsmm (sooty mangabey), and intermediate for HIV-2. We speculate that the increased rates of nonsynonymous changes in gp120 and gag coding sequences are due to viral escape from immune surveillance and are indicative of higher immunogenicity of these proteins in their hosts. Based on these results and available experimental data, we conclude that there is a positive correlation between lentiviral pathogenicity and immunogenicity of the Env and Gag proteins in a given host. This hypothesis is consistent with recent data suggesting that immune system activation or autoimmunity induced by viral antigens may be important in the pathogenesis of AIDS.

Amino Acids↗

Investigation of the human Rh blood group system in nonhuman primates and other species with serologic and Southern blot analysis.

To investigate the evolution of the Rh blood-group system in anthropoid apes, New and Old World monkeys, and nonprimate animals, serologic typing of erythrocytes from these species with antibodies specific for the human Rh blood-group antigens was performed. In addition, genomic DNA from these animals was analyzed on Southern blots with a human Rh-specific cDNA. Consistent with earlier reports, serologic results showed that gorilla and chimpanzee erythrocytes had epitopes recognized by human Rh D and c antisera, and gibbon erythrocytes were recognized by the c antisera. Surprisingly, some Old and New World monkeys also expressed a Rh c epitope on their erythrocytes. No erythrocytes from the nonprimate animals reacted specifically with any of the human Rh antisera. Southern blot analysis with a human Rh-specific cDNA probe detected Rh-related sequences in anthropoid apes, all New and Old World monkeys, and in most nonprimate animals tested. Although some Rh-related restriction fragments were conserved across species lines in primates, the Rh locus was more polymorphic in chimpanzees and gorillas than in humans. In addition, restriction fragments segregating with the presence of the D antigen in humans were present in the primate species that expressed the D antigen.

Animals↗

Organization and evolution of C4 and CYP21 genes in primates: importance of genomic segments.

The evolutionary relationship between two central major histocompatibility complex (MHC) genes, C4 and CYP21, was investigated by employing pulsed field gel electrophoresis (PFGE) and conventional restriction fragment length polymorphism (RFLP) analyses in human and nonhuman primates. Using Taq I in conjunction with C4 and CYP21 probes, it has been found that there are four major types of C4 genes [defined by 7.0, 6.4, 6.0, and 5.4 kilobases (kb) Taq I fragments] and two major types of CYP21 genes (3.7 and 3.2 kb fragments) in human and nonhuman primates including chimpanzee, gorilla, and orangutan. All of the eight possible combinations of C4 and CYP21 genes can be identified on one or more human ancestral haplotypes (AH). It is concluded that each of the major types of C4 and CYP21 (and each of the combinations between these) predated human speciation. PFGE analysis with Mlu I and Pvu I suggested that each C4+CYP21 segment has a specific length of 30-50 kb and that each AH carries one, two, three, or even more segments. In the case of C4, it is important to note that there is no simple relationship between the RFLP and the protein classifications. Thus, at least some of the expressed polymorphisms could be relatively recent in that they are carried by the same or different gene types. These findings are consistent with the hypothesis that MHC AHs have been formed from a large pool of specific genomic segments and that further haplospecific polymorphism has developed subsequently.

Animals↗

Neural network simulations of the primate oculomotor system. I. The vertical saccadic burst generator.

The performance of a neural network that simulates the vertical saccade-generating portion of the primate brain is evaluated. Consistent with presently available anatomical evidence, the model makes use of an eye displacement signal for its feedback. Its major features include a simple mechanism for resetting its integrator at the end of each saccade, the ability to generate staircases of saccades in response to stimulation of the superior colliculus, and the ability to account for the monotonic relation between motor error and the instantaneous discharge of presaccadic neurons of the superior colliculus without placing the latter within the local feedback loop. Several experimentally testable predictions about the effects of stimulation or lesion of saccade-related areas of the primate brain are made on the basis of model output in response to "stimulation" or "lesion" of model elements.

Animals↗

New cytogenetic techniques in the study of primate genome evolution.

Fixed metaphase chromosomes of different species and genera of Primates (five species of Macaca genus and Callithrix jacchus) have been studied after Alu I restriction enzyme digestion and DA-DAPI counterstaining, in the attempt to determine some qualitative characteristics of their DNAs and specifically of the DNA localized in the heterochromatic components of the karyotypes. The results have been discussed in the light of those already published on humans, confirming the potentiality of this approach in the study of the phyloevolutive relationships in Primates.

Animals↗

Primate evolution of a dispersed human repetitive DNA sequence.

A dispersed middle repetitive DNA sequence isolated originally from human chromosome 12 did not show homology with rodent DNA under standard conditions of Southern DNA blot analysis. The evolutionary relationship of this human repetitive DNA to that of other primates was investigated using three hybridization methods: DNA dot blot, Southern DNA blot analysis, and chromosome in situ hybridization. Homology with the human repetitive DNA was found throughout the suborder Anthropoidea, in fourteen ape and New and Old World monkey species. In addition, the human pattern of hybridization to noncentromeric regions of all chromosomes was seen. No hybridization by any of the three techniques was found in five species of the suborder Prosimii. The phenomenon of marked differences in sequence homology and copy number of dispersed repetitive DNA from closely related species has been observed in protozoans (Plasmodia), Drosophila, sea urchins, mice and the great apes (Hominoidea). We report here a similar phenomenon that may have occurred at an early stage in primate evolution.

Animals↗

Relationship between lectin binding properties and the expression of blood group ABH antigens in vascular endothelia and red blood cells from 18 primate species.

The reactivity was examined of horseradish peroxidase labelled Ulex europaeus agglutinin-I (UEA-I) and Griffonia simplicifolia agglutinin I-B4 (GSAI-B4) with red blood cells and vascular endothelium in formalin-fixed, paraffin embedded tissues from 18 primate species. The expression of blood group ABH antigens in these cells as well as secretions from other tissues was also examined by the indirect immunoperoxidase method using monoclonal anti-ABH antibodies as primary antibodies. In Prosimians and New World monkeys which lack ABH antigens on both red blood cells and endothelial cells, but produce these antigens in other tissue secretions, GSAI-B4 always reacted with both red blood cells and endothelial cells. In Old World monkeys, which express blood group antigens on endothelial cells but not on red blood cells, neither GSAI-B4 nor UEA-I reactivity were observed, except the endothelial cells from blood group B or O individuals occasionally reacted with GSAI-B4 or UEA-I, respectively. Although UEA-I reactivity was not observed in the endothelial cells of gibbon, it reacted with these cells from chimpanzees. In these two anthropoid apes, both endothelial cells and red blood cells expressed ABH antigens as in humans. These results suggest the close evolutionary relationship between the expression of blood group ABH antigens and lectin binding properties of red blood cells and endothelial cells in primate species.

ABO Blood-Group System↗

Orosomucoid typing of apes (family Pongidae) by isoelectric focusing: among primates do only humans have two functional orosomucoid loci?

It has been demonstrated that human orosomucoid (ORM) is controlled by more than one functional loci, while Macaca ORM is controlled by one locus. To examine the time when the ORM gene was duplicated in the evolution of primates, plasma samples from 118 apes (family Pongidae) belonging to 4 genera and 12 species were investigated for ORM polymorphism using isoelectric focusing followed by immunoprinting. The band patterns of ORM in the subfamily Ponginae showed quantitatively different products as in humans. A pedigree study of common chimpanzees supported the two-locus model for ORM. Gibbons (subfamily Hylobatinae) displayed highly variable band patterns, but the number of loci was not determined unequivocally. Thus, this study shows that duplication of the ORM gene in primates occurred either before or after the divergence of Hylobatinae and Ponginae, consistent with a previous prediction from the molecular evolutionary rate of ORM.

Alleles↗

The distribution of serum high density lipoprotein subfractions in non-human primates.

The ultracentrifugal flotation patterns in 1.2 g/ml solvent and ultracentrifugal gradient distribution of high density lipoproteins (HDL) from the primates--human, apes and monkeys--were determined, with emphasis on the gorilla species of apes and rhesus monkeys. Diets for non-human primates were commercial chow, which is low in cholesterol. Molecular weights and protein, cholesterol, phospholipid and triglyceride compositions of various density fractions were determined on human, gorilla and rhesus HDL. The HDL2/HDL3 ratio was determined from the two peaks observed upon flotation in high salt in the analytical ultracentrifuge. The HDL2 of all three species of apes--gorillas (Gorilla gorilla), chimpanzees (Pan troglodytes) and orangutans (Pongo pygmaeus)--was always greater than HDL3, while that of all six species of Old World monkeys--Rhesus (Macaca mulatta), sooty mangabeys (Cercocebus atys), cynomolgus (Macaca fascicularis), stumptails, (Macaca arctoides) patas (Erythrocebus patas) and African greens (Cercopithecus aethiops)--was less. In addition, the HDL3 concentration in five gorillas was about 15 mg/dl as cholesterol while the HDL2 concentration was 92 mg/dl, much lower and higher, respectively, than humans. HDL2 of gorillas was similar in density and molecular weight to that of humans. The distribution of densities in gorilla HDL was predominantly in HDL2, while rhesus HDL usually, but not always, was unimodal, having a density distribution similar in heterogeneity to human HDL3, but somewhat less dense (peaking at 1.109 vs. 1.129 g/ml). The molecular weight of rhesus HDL was about the same as human HDL3 in all three density subfractions and at the peak density.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Sex differences in mutation rate in higher primates estimated from AMG intron sequences.

To study sex differences in mutation rate in primates, we sequenced the third introns of the AMGX and AMGY genes from humans, orangutans, and squirrel monkeys and estimated that the male-to-female ratio of mutation rate is alpha = 5.14 with the 95% confidence interval (2.42, 16.6). Combining this data set and the data sets from ZFX/ZFY and SMCX/SMCY introns, we obtained an estimate of alpha = 5.06 with the 95% confidence interval reduced to (3.24, 8.79). The alpha value is significantly higher in higher primates than in rodents.

Animals↗

Evolution of the primate androgen receptor: a structural basis for disease.

Androgen effects mediated by the androgen receptor (AR) are essential for male reproductive development and virilization. Comparison of AR DNA coding sequence from five primate species, Homo sapiens (human), Pan troglodytes (chimpanzee), Papio hamadryas (baboon), Macaca fascicularis (macaque), and Eulemur fulvus collaris (collared brown lemur), supports their phylogeny with complete conservation of the DNA and steroid binding domain protein sequence. A linear increase in trinucleotide repeat expansion of homologous CAG and GGC sequences occurs in the NH2-terminal transcriptional activation region and is proportional to the time of species divergence. A serine phosphate/glutamine repeat interaction is observed where increasing CAG repeat length is associated with an increased rate of serine 94 phosphorylation. Disparity in the calculated and apparent molecular weight with CAG repeat expansion of an AR NH2-terminal fragment suggests self-aggregation with increasing glutamine repeat length into the pathological range. These results suggest that a CAG/glutamine repeat expanded during divergence of the higher primate species, which may have a direct effect on AR structure and support a common pathway in CAG trigenic diseases in the pathophysiology of neurodegeneration observed in X-linked spinal bulbar and muscular atrophy.

Amino Acid Sequence↗