The members of the RH gene family (RH50 and RH30) followed different evolutionary pathways

Abnormalities in plasma composition of essential fatty acids (EFAs) may be associated with the etiology of pruritus and other skin problems in patients undergoing hemodialysis. To study whether an oral supplementation with omega-6 (n-6) EFAs would restore deranged plasma EFAs and ameliorate skin symptoms, 9 and 7 dialysis patients were randomly assigned to receive either gamma-linolenic acid (GLA)-rich evening primrose oil (EPO) or linoleic acid (LA) (2 g/day each) for 6 weeks. Plasma concentrations of EFA were analyzed by gas chromatography and uremic skin symptoms were assessed for dryness, pruritus and erythema by questionnaire and visual inspection in a double-blind manner. The patients given EPO exhibited a significant (p < 0.05) increase in plasma dihomo-gamma-linolenic acid (a precursor of anti-inflammatory prostaglandin E1) with no concomitant change in plasma arachidonic acid (a precursor of pro-inflammatory prostaglandin E2 and leukotriene B4). In contrast, those given LA exhibited a significant (p < 0.05) increase in LA but not in any other n-6 EFAs, whereas they exhibited a significant (p < 0.05) decrease in plasma docosahexaenoic acid. The patients given EPO showed a significant (p < 0.05) improvement in the skin scores for the three different uremic skin symptoms over the baseline values and a trend toward a greater improvement (0.05 < p < 0.1) in pruritus scores than those given LA. Results indicate that GLA-rich EPO would be a more favorable supplemental source than LA in terms of shifting eicosanoid metabolism toward a less inflammation status through modifying plasma concentrations of their precursor n-6 EFAs. Further studies are required to confirm the efficacy and safety of EPO therapy for the treatment of uremic pruritus.     

Evolution of the human RH (rhesus) blood group genes: a 50 year old prediction (partially) fulfilled

Almost exactly 50 years ago, R. A. Fisher and R. Race proposed a model for the evolution of the RH (rhesus) genes in which the less common haplotypes were derived from the commoner ones by recombination, and in which the gene order was D-C-E. No direct-evidence bearing on this model was available then, and has not been until now. Here we present evidence for non-reciprocal intergenic exchange (gene conversion) occurring once in human history to generate the common RHCE allele, Ce. We have also used new polymorphisms to construct haplotypes which suggest that intragenic recombination played a major role in the generation of the less common haplotypes, but only if RHD lies 3' of RHCE, i.e. the order is C-E-D. We provide both genetic and physical evidence supporting this arrangement.     

Organization of the human natriuretic peptide receptor A gene

We have determined the structural organization of the human natriuretic peptide receptor A (hNPRA) gene without screening the genomic library. Based on the information for the cDNA of hNPRA, we amplified some fragments of the long polymerase chain reaction (PCR) products covering all genomic sequences of the gene and directly sequenced the products after extraction and purification. The hNPRA gene spans approximately 16 kb and contains 22 exons and 21 introns. All of the exon-intron junction sequences coincide with the GT/AG consensus sequence. The sequence encoding the transmembrane domain, one part of the hNPRA topological structure, exists in exon 7. The results of this first study, determination of the hNPRA gene structure, will facilitate further genetic analysis of the hNPRA gene and its related diseases.     

A general model of carcinogenesis (I)--Tumor evolution and gene deletion

Carcinogenesis is functionally a deletion alteration rather than addition of genetic information. Repressor genes may be more sensitive to 'neutral' mutations of DNA than those of structural genes, since selection pressure for deletion of repressors is extremely low in multicellular organisms. Dysfunction of repressors caused by genomic mutation induces autonomic expression of structural genes which is programmed a priori in each cell. Tumor progression can be explained by this deletion model with abnormal DNA repair. Alteration of DNA repairing units may be the initial mutation in carcinogenesis.     

Intron loss and gain during evolution of the catalase gene family in angiosperms

Angiosperms (flowering plants), including both monocots and dicots, contain small catalase gene families. In the dicot, Arabidopsis thaliana, two catalase (CAT) genes, CAT1 and CAT3, are tightly linked on chromosome 1 and a third, CAT2, which is more similar to CAT1 than to CAT3, is unlinked on chromosome 4. Comparison of positions and numbers of introns among 13 angiosperm catalase genomic sequences indicates that intron positions are conserved, and suggests that an ancestral catalase gene common to monocots and dicots contained seven introns. Arabidopsis CAT2 has seven introns; both CAT1 and CAT3 have six introns in positions conserved with CAT2, but each has lost a different intron. We suggest the following sequence of events during the evolution of the Arabidopsis catalase gene family. An initial duplication of an ancestral catalase gene gave rise to CAT3 and CAT1. CAT1 then served as the template for a second duplication, yielding CAT2. Intron losses from CAT1 and CAT3 followed these duplications. One subclade of monocot catalases has lost all but the 5'-most and 3'-most introns, which is consistent with a mechanism of intron loss by replacement of an ancestral intron-containing gene with a reverse-transcribed DNA copy of a fully spliced mRNA. Following this event of concerted intron loss, the Oryza sativa (rice, a monocot) CAT1 lineage acquired an intron in a novel position, consistent with a mechanism of intron gain at proto-splice sites.     

Rapid evolution in a conserved gene family. Evolution of the actin gene family in the sea urchin genus Heliocidaris and related genera

Camarodont sea urchins possess a rapidly evolving actin gene family whose members are expressed in distinct cell lineages in a developmentally regulated fashion. Evolutionary changes in the actin gene family of echinoids include alterations in number of family members, site of expression, and gene linkage, and a dichotomy between rapidly and slowly evolving isoform-specific 3' untranslated regions. We present sequence comparisons and an analysis of the actin gene family in two congeneric sea urchins that develop in radically different modes, Heliocidaris erythrogramma and H. tuberculata. The sequences of several actin genes from the related species Lytechinus variegatus are also presented. We compare the features of the Heliocidaris and Lytechinus actin genes to those of the the actin gene families of other closely related sea urchins and discuss the nature of the evolutionary changes among sea urchin actins and their relationship to developmental mode.     

Structure of the human type XIX collagen (COL19A1) gene, which suggests it has arisen from an ancestor gene of the FACIT family

Type XIX collagen is a newly discovered member of the FACIT (fibril-associated collagens with interrupted triple helices) group of extracellular matrix proteins. Based on the primary structure, type XIX collagen is thought to act as a cross-bridge between fibrils and other extracellular matrix molecules. Here we describe the complete exon/intron organization of COL19A1 and show that it contains 51 exons, spanning more than 250 kb of genomic DNA. The comparison of exon structures of COL19A1 and other FACIT family genes revealed several similarities among these genes. The structure of exons encoding the noncollagenous (NC) 1-collagenous (COL) 1-NC 2-COL 2-NC 3-COL 3-NC 4 domain of the alpha1(XIX) chain is similar to that of the NC 1-COL 1-NC 2-COL 3-NC 3 domain of the alpha2(IX) chain except for the NC 3 domain of alpha1(XIX). The exons encoding the COL 5-NC 6 domain of alpha1(XIX) are also similar to those of the COL 3-NC 4 domain of alpha1(IX) chain. Previously, COL19A1 was mapped to human chromosome 6q12-q14, where COL9A1 is also located. Likewise, the present work shows that the mouse Col19a1 gene is located on mouse chromosome 1, region A3, where Col9a1 has also been mapped. Taken together, the data suggest that COL19A1 and COL9A1 (Col19a1 and Col9a1) were duplicated from the same ancestor gene of the FACIT family. Three CA repeat markers with high heterozygosity were found in COL19A1. These markers may be useful for linkage analysis of age-related inheritable diseases involved in eyes and/or brain.     

A common base for psychotherapy and family therapy.

Describes the paradigms of psychoanalysis and family therapy and contends, based on clinical experience, that they have common links. For example, the insight sought in a psychoanalytic approach led inadvertently to changed interactions sought in family therapy, and changed interactions sought in family therapy led inadvertently to insight. The relationships among, sources of accuracy and distortion in formulation, sources of agreement and disagreement, and the role of real interactions in preserving object- and self-representations are explored. It is hypothesized that the change agent for both psychoanalysis and family therapy is the same. That is, the provision of unusual interactions in an emotionally significant relationship makes maintenance of existing self- and object-representations impossible. New mental operations that result constitute the change in individuals and the possibility of growth and new adaptations. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Molecular biology of the human phenol sulfotransferase gene family

Cytosolic phenol sulfotransferases (PST) catalyze the sulfation/sulfonation of various phenolic agents, including catecholamines, thyroid hormones, and drugs (e.g., minoxidil and acetaminophen), which usually results in the inactivation and subsequent excretion of the compound. Our recent efforts have focused on the cloning and sequencing of the human gene family encoding the PST isozymes, and the results are summarized in this article. Multiple PST cDNA isolates have been cloned in various laboratories representing alleles of three phenol sulfotransferase gene loci termed as STP1, STP2, and STM. All three genes have been mapped precisely to a small region on human chromosome 16p12.1-p11.2 (homologous to mouse chromosome 7). The two most closely related genes, STP1 and STP2, encode isozymes of phenol-preferring PST (P-PST) and have been mapped to a single genomic cosmid clone, thus in proximity to one another. The STM gene encoding the monoamine neurotransmitter-preferring PST (M-PST) exhibits a lower level of similarity relative to STP1 and STP2. Genomic clones have been sequenced to determine the genomic organization for each of the three highly related genes. All contain seven coding exons, with conserved intron-exon boundaries. Sequencing of individual cDNA isolates from various tissues has revealed heterogeneity in the 5' nontranslated regions, likely due to tissue-specific promoter utilization (or perhaps alternative splicing). DNA and protein polymorphisms have been identified in the population and may be useful for molecular genetic studies of the variability in the metabolism of catecholamines, thyroid hormones, and phenolic drugs, and possibly neuropsychiatric or other metabolic disorders.     

Organization and sequence of the human gene for the mitochondrial citrate transport protein

Basic fibroblast growth factor (FGF-2) is a potent mitogen which is required for normal development, particularly the development of the skeletal system, where the inhibition of FGF binding to its receptor results in various skeletal malformations. The present study employed a newly engineered line of FGF-2 transgenic mice to determine the effects of overexpressing FGF-2 on limb bone ontogeny. We collected radiographic and weight data longitudinally and obtained the length, proximal, distal, and minimum diaphyseal widths of the humerus, femur, and tibia. Because growth is nonlinear with respect to time, we used the Gompertz mathematical model to obtain parameters describing rate and timing for each individual for each measurement. Differences in the parameters due to genotype and sex were subsequently tested with ANOVA. Transgenic animals exhibited consistently shorter limb bones which were generally wider at the epiphyses than those of controls. Parameters of early growth, including initial size and proportional rate of growth, appeared to be most directly responsible for significant differences in final size; however, exponential decay of growth was also a marginally significant factor. There were no differences between the genotypes in body weight, indicating that the shape anomalies observed in transgenic mice were a direct result of the action of FGF-2 rather than a general runting phenomenon.     

Clonal composition of malignant fibrous histiocytoma: analysis by PCR-based assay of the human androgen receptor gene (HUMARA)

Poly(A)+ mRNA was isolated from leaves of potato plants (Solanum tuberosum L. cv. Desiree) according to standard protocols. This poly(A)+ mRNA was injected via glass microcapillaries into oocytes that were surgically removed from the African clawed toad Xenopus laevis. As a control, oocytes were either injected with H2O or remained untreated. Three days after injection the oocytes were analyzed by two electrode voltage clamping. Current voltage analysis revealed that a K+ channel from potato was functionally expressed in injected oocytes. The identity of this K+ channel was confirmed by its substrate specificity and a shift in the reversal potential. In particular, when the outside K+ concentration was increased the reversal potential of poly(A)+ injected oocytes shifted to more positive values. Furthermore, K+ outward currents declined when the outside K+ concentration was raised from 0.1 to 100 mM. Inward currents increased with an elevation of the K+ concentration. Several pharmaceuticals were tested for their potential to block this K+ channel. As a result, the channel was completely blocked by BaCl2. A three state reaction kinetic model was used to simulate the currents through the K+ transport protein as function of the extracellular K+ concentration. In particular, the simulation revealed current voltage relations that exactly matched the measured ones. Saturation of current voltage curves emerged from the simulation as a consequence of high extracellular potassium concentration.     

The human serum paraoxonase/arylesterase gene (PON1) is one member of a multigene family

A physiological role for paraoxonase (PON1) is still uncertain, but it catalyzes the hydrolysis of toxic organophosphates. Evidence that the human genome contains two PON1-like genes, designated PON2 and PON3, is presented here. Human PON1 and PON2 each have nine exons, and the exon/intron junctions occur at equivalent positions. PON1 and PON2 genes are both on chromosome 7 in human and on chromosome 6 in the mouse. Turkey and chicken, like most birds, lack paraoxonase activity and are very susceptible to organophosphates. However, they have a PON-like gene with approximately 70% identity with human PON1, PON2, and PON3. Another unexpected finding is that the deduced amino acid sequences of PON2 in human, mouse, dog, turkey, and chicken and of human PON3 are all missing the amino acid residue 105, which is lysine in human PON1. The expanded number of PON genes will have important implications for future experiments designed to discover the individual functions, catalytic properties, and physiological roles of the paraoxonases.     

Long term trends in the evolution of H(3) HA1 human influenza type A

We have studied the HA1 domain of 254 human influenza A(H3N2) virus genes for clues that might help identify characteristics of hemagglutinins (HAs) of circulating strains that are predictive of that strain's epidemic potential. Our preliminary findings include the following. (i) The most parsimonious tree found requires 1,260 substitutions of which 712 are silent and 548 are replacement substitutions. (ii) The HA1 portion of the HA gene is evolving at a rate of 5.7 nucleotide substitutions/year or 5.7 x 10(-3) substitutions/site per year. (iii) The replacement substitutions are distributed randomly across the three positions of the codon when allowance is made for the number of ways each codon can change the encoded amino acid. (iv) The replacement substitutions are not distributed randomly over the branches of the tree, there being 2.2 times more changes per tip branch than for non-tip branches. This result is independent of how the virus was amplified (egg grown or kidney cell grown) prior to sequencing or if sequencing was carried out directly on the original clinical specimen by PCR. (v) These excess changes on the tip branches are probably the result of a bias in the choice of strains to sequence and the detection of deleterious mutations that had not yet been removed by negative selection. (vi) There are six hypervariable codons accumulating replacement substitutions at an average rate that is 7.2 times that of the other varied codons. (vii) The number of variable codons in the trunk branches (the winners of the competitive race against the immune system) is 47 +/- 5, significantly fewer than in the twigs (90 +/- 7), which in turn is significantly fewer variable codons than in tip branches (175 +/- 8). (viii) A minimum of one of every 12 branches has nodes at opposite ends representing viruses that reside on different continents. This is, however, no more than would be expected if one were to randomly reassign the continent of origin of the isolates. (ix) Of 99 codons with at least four mutations, 31 have ratios of non-silent to silent changes with probabilities less than 0.05 of occurring by chance, and 14 of those have probabilities <0.005. These observations strongly support positive Darwinian selection. We suggest that the small number of variable positions along the successful trunk lineage, together with knowledge of the codons that have shown positive selection, may provide clues that permit an improved prediction of which strains will cause epidemics and therefore should be used for vaccine production.     

Evidence of independent gene duplications during the evolution of archaeal and eukaryotic family B DNA polymerases

Eukaryotes and archaea both possess multiple genes coding for family B DNA polymerases. In animals and fungi, three family B DNA polymerases, alpha, delta, and epsilon, are responsible for replication of nuclear DNA. We used a PCR-based approach to amplify and sequence phylogenetically conserved regions of these three DNA polymerases from Giardia intestinalis and Trichomonas vaginalis, representatives of early-diverging eukaryotic lineages. Phylogenetic analysis of eukaryotic and archaeal paralogs suggests that the gene duplications that gave rise to the three replicative paralogs occurred before the divergence of the earliest eukaryotic lineages, and that all eukaryotes are likely to possess these paralogs. One eukaryotic paralog, epsilon, consistently branches within archaeal sequences to the exclusion of other eukaryotic paralogs, suggesting that an epsilon-like family B DNA polymerase was ancestral to both archaea and eukaryotes. Because crenarchaeote and euryarchaeote paralogs do not form monophyletic groups in phylogenetic analysis, it is possible that archaeal family B paralogs themselves evolved by a series of gene duplications independent of the gene duplications that gave rise to eukaryotic paralogs.