Comparative genomic analysis of eutherian interferon genes.

The eutherian interferons were implicated as paradigmatic effector proteins in innate and acquired immunity. Yet, familiar interferon classification and nomenclature disagreed with functional genomics, phylogenetic and evolutionary analyses. Using eutherian comparative genomic analysis protocol and 35 public eutherian reference genomic sequence data sets, the present analysis attempted to resolve major disagreements in descriptions of eutherian interferons. Among 836 eutherian interferon potential coding sequences, the tests of reliability of eutherian public genomic sequences annotated, in aggregate, 495 complete coding sequences that were partitioned into supercluster IF1 and supercluster IF2 gene data sets. There were 29 human class 2 cytokine genes described, including initially described human IF1IC2 gene. There was convergence between nonhomologous eutherian supercluster IF1 and supercluster IF2 protein primary structures including common cysteine amino acid residues implicated in disulfide bonding. The integrated gene annotations, phylogenetic analysis and protein molecular analysis proposed revised and updated classification and nomenclature of eutherian interferons.

Comparative genomic analysis of eutherian fibroblast growth factor genes.

BACKGROUND: The eutherian fibroblast growth factors were implicated as key regulators in developmental processes. However, there were major disagreements in descriptions of comprehensive eutherian fibroblast growth factors gene data sets including either 18 or 22 homologues. The present analysis attempted to revise and update comprehensive eutherian fibroblast growth factor gene data sets, and address and resolve major discrepancies in their descriptions using eutherian comparative genomic analysis protocol and 35 public eutherian reference genomic sequence data sets. RESULTS: Among 577 potential coding sequences, the tests of reliability of eutherian public genomic sequences annotated most comprehensive curated eutherian third-party data gene data set of fibroblast growth factor genes including 267 complete coding sequences. The present study first described 8 superclusters including 22 eutherian fibroblast growth factor major gene clusters, proposing their updated classification and nomenclature. CONCLUSIONS: The integrated gene annotations, phylogenetic analysis and protein molecular evolution analysis argued that comprehensive eutherian fibroblast growth factor gene data set classifications included 22 rather than 18 homologues.

Comparative genomic analysis of eutherian tumor necrosis factor ligand genes.

The present analysis made attempts to resolve discrepancies in descriptions of eutherian tumor necrosis factor ligand genes implicated in cell signalling pathways, as well as in major physiological and pathological processes. Among 455 potential coding sequences, the eutherian comparative genomic analysis protocol annotated 211 complete coding sequences using public genomic sequence assemblies. The most comprehensive third party data gene data set first described 8 superclusters of eutherian tumor necrosis factor ligand genes, including 18 major gene clusters. The integrated gene annotations, phylogenetic analysis, and protein molecular evolution analysis proposed new classification and nomenclature of eutherian tumor necrosis factor ligand genes, as new framework of future experiments.

Comparative genomic analysis of eutherian ribonuclease A genes.

The present study attempted to update comprehensive eutherian ribonuclease A gene data sets, using public eutherian genomic sequence data sets and new genomics and molecular evolution tests. Among 448 ribonuclease A potential coding sequences, the present analysis annotated 255 complete coding sequences. The most comprehensive data set of eutherian ribonuclease A genes first characterized 13 major gene clusters, 9 of which showed evidence of differential gene expansions. In addition, the present analysis described common predicted promoter regions of eutherian ribonuclease A genes. The present study also attempted to resolve discrepancies in descriptions of eutherian ribonuclease A genes. Thus, the integrated gene annotations, phylogenetic analysis and protein molecular evolution analysis proposed new classification and nomenclature of eutherian ribonuclease A genes, as new framework of future experiments.

Comparative genomic analysis of eutherian interferon-γ-inducible GTPases.

The interferon-γ-inducible GTPases, IFGGs, are intracellular proteins involved in immune response against pathogens. A comprehensive comparative genomic review and analysis of eutherian IFGGs was carried out using public genomic sequences. The 64 eutherian IFGG genes were examined in detail and annotated. The eutherian IFGG promoter types were first catalogued followed by a phylogenetic analysis of eutherian IFGGs, which described five major IFGG clusters. The patterns of differential gene expansions and protein regions that may regulate IFGG catalytic features suggested a new classification of eutherian IFGGs. This mini-review has also provided new tests of reliability of public genomic sequences as well as tests of protein molecular evolution.

Revised eutherian gene collections.

OBJECTIVES: The most recent research projects in scientific field of eutherian comparative genomics included intentions to sequence every extant eutherian species genome in foreseeable future, so that future revisions and updates of eutherian gene data sets were expected. DATA DESCRIPTION: Using 35 public eutherian reference genomic sequence assemblies and free available software, the eutherian comparative genomic analysis protocol RRID:SCR_014401 was published as guidance against potential genomic sequence errors. The protocol curated 14 eutherian third-party data gene data sets, including, in aggregate, 2615 complete coding sequences that were deposited in European Nucleotide Archive. The published eutherian gene collections were used in revisions and updates of eutherian gene data set classifications and nomenclatures that included gene annotations, phylogenetic analyses and protein molecular evolution analyses.

Author Correction: Comparative genomic analysis of eutherian connexin genes.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Positive selection in prion protein.

The prion diseases, such as Creutzfeldt-Jakob disease of humans and bovine spongiform encephalopathy, involve the aberrant metabolism and accumulation of prion protein PrP. There are three contradictory hypotheses about evolution of prion protein gene PRNP. Population genetic studies have proposed that PRNP could be under balancing selection, strong purifying selection, or mainly positive selection. We made use of the maximum likelihood tests for detection of positive selection at the amino acid level and present availability of PRNP coding sequences to contribute to these disagreements. Positive selection could occur at amino acids residing in active sites, and at amino acids involved in protein-protein interactions. Thus we tested a hypothesis that positive selection at the amino acid level in PrP might have taken place in human and related species from the superordinal group Euarchonta, as well as in bovine and related species from the superordinal clade Laurasiatheria. Our study and the present experimental evidences indicate that positive selection at the amino acid level might have taken place in the PrP signal sequences and conformationally plastic PrP regions, as well as at the protein X binding sites.

Comparative genomic analysis of eutherian connexin genes.

The eutherian connexins were characterized as protein constituents of gap junctions implicated in cell-cell communications between adjoining cells in multiple cell types, regulation of major physiological processes and disease pathogeneses. However, conventional connexin gene and protein classifications could be regarded as unsuitable in descriptions of comprehensive eutherian connexin gene data sets, due to ambiguities and inconsistencies in connexin gene and protein nomenclatures. Using eutherian comparative genomic analysis protocol and 35 public eutherian reference genomic sequence data sets, the present analysis attempted to update and revise comprehensive eutherian connexin gene data sets, and address and resolve major discrepancies in their descriptions. Among 631 potential coding sequences, the tests of reliability of eutherian public genomic sequences annotated, in aggregate, 349 connexin complete coding sequences. The most comprehensive curated eutherian connexin gene data set described 21 major gene clusters, 4 of which included evidence of differential gene expansions. For example, the present gene annotations initially described human CXNK1 gene and annotated 22 human connexin genes. Phylogenetic tree calculations and calculations of pairwise nucleotide sequence identity patterns proposed revised and updated phylogenetic classification of eutherian connexin genes. Therefore, the present study integrating gene annotations, phylogenetic analysis and protein molecular evolution analysis proposed new nomenclature of eutherian connexin genes and proteins.

Comparative genomic analysis of eutherian adiponectin genes.

The present study proposed updated and standardized classification and nomenclature of eutherian adiponectin genes implicated in regulation of systemic metabolism and inflammation and activation of classical complement pathway. The revisions of comprehensive adiponectin gene data sets used eutherian comparative genomic analysis protocol and public reference genomic sequence assemblies. Among 438 potential coding sequences, the tests of reliability of eutherian public genomic sequences annotated most comprehensive curated third-party data gene data set of eutherian adiponectin genes that included 211 complete coding sequences. There were 18 major gene clusters of eutherian adiponectin genes described, one of which included evidence of differential gene expansions. For example, the present analysis initially described human ADIF2 and ADIR genes. Finally, the tests of protein molecular evolution using relative synonymous codon usage statistics confirmed protein primary structure similarities between eutherian adiponectins and tumor necrosis factor ligands.

Comparative genomic analysis of prion genes.

BACKGROUND: The homologues of human disease genes are expected to contribute to better understanding of physiological and pathogenic processes. We made use of the present availability of vertebrate genomic sequences, and we have conducted the most comprehensive comparative genomic analysis of the prion protein gene PRNP and its homologues, shadow of prion protein gene SPRN and doppel gene PRND, and prion testis-specific gene PRNT so far. RESULTS: While the SPRN and PRNP homologues are present in all vertebrates, PRND is known in tetrapods, and PRNT is present in primates. PRNT could be viewed as a TE-associated gene. Using human as the base sequence for genomic sequence comparisons (VISTA), we annotated numerous potential cis-elements. The conserved regions in SPRNs harbour the potential Sp1 sites in promoters (mammals, birds), C-rich intron splicing enhancers and PTB intron splicing silencers in introns (mammals, birds), and hsa-miR-34a sites in 3'-UTRs (eutherians). We showed the conserved PRNP upstream regions, which may be potential enhancers or silencers (primates, dog). In the PRNP 3'-UTRs, there are conserved cytoplasmic polyadenylation element sites (mammals, birds). The PRND core promoters include highly conserved CCAAT, CArG and TATA boxes (mammals). We deduced 42 new protein primary structures, and performed the first phylogenetic analysis of all vertebrate prion genes. Using the protein alignment which included 122 sequences, we constructed the neighbour-joining tree which showed four major clusters, including shadoos, shadoo2s and prion protein-likes (cluster 1), fish prion proteins (cluster 2), tetrapode prion proteins (cluster 3) and doppels (cluster 4). We showed that the entire prion protein conformationally plastic region is well conserved between eutherian prion proteins and shadoos (18-25% identity and 28-34% similarity), and there could be a potential structural compatibility between shadoos and the left-handed parallel beta-helical fold. CONCLUSION: It is likely that the conserved genomic elements identified in this analysis represent bona fide cis-elements. However, this idea needs to be confirmed by functional assays in transgenic systems.

Comparative genomic analysis of eutherian kallikrein genes.

The present study made attempts to update and revise eutherian kallikrein genes implicated in major physiological and pathological processes and in medical molecular diagnostics. Using eutherian comparative genomic analysis protocol and free available genomic sequence assemblies, the tests of reliability of eutherian public genomic sequences annotated most comprehensive curated third party data gene data set of eutherian kallikrein genes including 121 complete coding sequences among 335 potential coding sequences. The present analysis first described 13 major gene clusters of eutherian kallikrein genes, and explained their differential gene expansion patterns. One updated classification and nomenclature of eutherian kallikrein genes was proposed, as new framework of future experiments.

The complete set of ribosomal proteins from the marine sponge Suberites domuncula.

The siliceous marine sponge Suberites domuncula is a member of the most ancient and simplest extant phylum of multicellular animals-Porifera, which have branched off first from the common ancestor of all Metazoa. We have determined primary structures of 79 ribosomal proteins (r-proteins) from S. domuncula: 32 proteins from the small ribosomal subunit and 47 proteins from the large ribosomal subunit. Only L39 and L41 polypeptides (51 and 25 residues long in rat, respectively) are missing. The sponge S. domuncula is, after nematode Caenorhabditis elegans and insect Drosophila melanogaster the third representative of invertebrates with known amino acid sequences of all r-proteins. The comparison of S. domuncula r-proteins with r-proteins from D. melanogaster, C. elegans, rat, Arabidopsis thaliana and Saccharomyces cerevisiae revealed very interesting findings. The majority of the sponge r-proteins are more similar to their homologues from rat, than to those either from invertebrates C. elegans and D. melanogaster, or yeast and plant. With few exceptions, the overall sequence conservation between sponge and rat r-proteins is 80% or higher. The phylogenetic tree of concatenated r-proteins from 6 eukaryotic species (rooted with archaeal r-proteins) has the shortest branches connecting sponge and rat. Both model invertebrate organisms experienced recently accelerated evolution and therefore sponge r-proteins very probably better reflect structures of proteins in the ancestral metazoan ribosome, which changed only little during metazoan evolution. Furthermore, r-proteins from the plant A. thaliana are significantly closer to metazoan r-proteins than are those from the yeast S. cerevisiae.

Curated eutherian third party data gene data sets.

The free available eutherian genomic sequence data sets advanced scientific field of genomics. Of note, future revisions of gene data sets were expected, due to incompleteness of public eutherian genomic sequence assemblies and potential genomic sequence errors. The eutherian comparative genomic analysis protocol was proposed as guidance in protection against potential genomic sequence errors in public eutherian genomic sequences. The protocol was applicable in updates of 7 major eutherian gene data sets, including 812 complete coding sequences deposited in European Nucleotide Archive as curated third party data gene data sets.

The prion protein gene: identifying regulatory signals using marsupial sequence.

The function of the prion protein gene (PRNP) and its normal product PrP(C) is elusive. We used comparative genomics as a strategy to understand the normal function of PRNP. As the reliability of comparisons increases with the number of species and increased evolutionary distance, we isolated and sequenced a 66.5 kb BAC containing the PRNP gene from a distantly related mammal, the model Australian marsupial Macropus eugenii (tammar wallaby). Marsupials are separated from eutherians such as human and mouse by roughly 180 million years of independent evolution. We found that tammar PRNP, like human PRNP, has two exons. Prion proteins encoded by the tammar wallaby and a distantly related marsupial, Monodelphis domestica (Brazilian opossum) PRNP contain proximal PrP repeats with a distinct, marsupial-specific composition and a variable number. Comparisons of tammar wallaby PRNP with PRNPs from human, mouse, bovine and ovine allowed us to identify non-coding gene regions conserved across the marsupial-eutherian evolutionary distance, which are candidates for regulatory regions. In the PRNP 3' UTR we found a conserved signal for nuclear-specific polyadenylation and the putative cytoplasmic polyadenylation element (CPE), indicating that post-transcriptional control of PRNP mRNA activity is important. Phylogenetic footprinting revealed conserved potential binding sites for the MZF-1 transcription factor in both upstream promoter and intron/intron 1, and for the MEF2, MyT1, Oct-1 and NFAT transcription factors in the intron(s). The presence of a conserved NFAT-binding site and CPE indicates involvement of PrP(C) in signal transduction and synaptic plasticity.

Third party data gene data set of eutherian growth hormone genes.

Among 146 potential coding sequences, the most comprehensive eutherian growth hormone gene data set annotated 100 complete coding sequences. The eutherian comparative genomic analysis protocol first described 5 major gene clusters of eutherian growth hormone genes. The present updated gene classification and nomenclature of eutherian growth hormone genes integrated gene annotations, phylogenetic analysis and protein molecular evolution analysis into new framework of future experiments. The curated third party data gene data set of eutherian growth hormone genes was deposited in European Nucleotide Archive under accession numbers LM644135-LM644234.

Initial description of primate-specific cystine-knot Prometheus genes and differential gene expansions of D-dopachrome tautomerase genes.

Using eutherian comparative genomic analysis protocol and public genomic sequence data sets, the present work attempted to update and revise two gene data sets. The most comprehensive third party annotation gene data sets of eutherian adenohypophysis cystine-knot genes (128 complete coding sequences), and d-dopachrome tautomerases and macrophage migration inhibitory factor genes (30 complete coding sequences) were annotated. For example, the present study first described primate-specific cystine-knot Prometheus genes, as well as differential gene expansions of D-dopachrome tautomerase genes. Furthermore, new frameworks of future experiments of two eutherian gene data sets were proposed.

Shadoo, a new protein highly conserved from fish to mammals and with similarity to prion protein.

We report evidence from cDNA isolation and expression analysis as well as analyses of genome, expressed sequence tag (EST), cDNA and expression databases for a new gene named SPRN (shadow of prion protein). SPRN comprises two exons, with the open reading frame (ORF) contained within exon 2, and codes for a protein of 130-150 amino acids named Shadoo (Japanese shadow), predicted to be extracellular and GPI-anchored. The SPRN gene was found in fish (zebrafish, Fugu) and mammals (mouse, rat, human). Conservation of order and transcription orientation of two proximal genes between fishes and mammals strongly indicates gene orthology. Sequence comparison shows: a highly conserved N-terminal signal sequence; Arg-rich basic region containing up to six tetrarepeats of consensus XXRG (where X is G, A or S); a hydrophobic region of 20 residues with strong homology to PrP; a less conserved C-terminal domain containing a conserved glycosylation motif; and a C-terminal peptide predicted to be a signal sequence for glycophosphotidylinositol (GPI)-anchor attachment. Fish Shadoos (Sho) show well conserved sequences (identity 54%) over 106 amino acids (zebrafish length), and conservation among the mammalian sequences is very high (identity 81-96%). The fish and mammalian sequences are also well conserved, particularly for zebrafish, to beyond the end of the hydrophobic sequence (identity 41-53%, 78 amino acids, zebrafish length). The overall structure appears closely related to prion proteins (PrPs), although the C-terminal domains of Shos are quite different from those of PrPs, for which conformational changes in mammals are implicated in disease. The structural similarity is particularly interesting given recent reports of three new genes with similarities to PrPs found in Fugu (PrP-like, PrP-461/stPrP-1 and stPrP-2) and other fish, but for which direct evolution to higher vertebrate PrPs is unlikely and for which no other mammalian homologues have been found. Database information indicates expression of SPRN in embryo, brain and retina of mouse and rat, hippocampus of human, and in embryo and retina of zebrafish, and we directly confirmed a strikingly specific expression of the mammalian (human, mouse, rat) transcripts in whole brain. This result together with some common structural features led to the suggestive hypothesis of a possible functional link between mammalian PrP and Sho proteins.

Third party annotation gene data set of eutherian lysozyme genes.

The eutherian comparative genomic analysis protocol annotated most comprehensive eutherian lysozyme gene data set. Among 209 potential coding sequences, the third party annotation gene data set of eutherian lysozyme genes included 116 complete coding sequences that first described seven major gene clusters. As one new framework of future experiments, the present integrated gene annotations, phylogenetic analysis and protein molecular evolution analysis proposed new classification and nomenclature of eutherian lysozyme genes.

Comparative genomic analysis of eutherian Mas-related G protein-coupled receptor genes.

The present study made attempts to update comprehensive eutherian Mas-related G protein-coupled receptor gene data sets, using public eutherian genomic sequence data sets and new genomics and molecular evolution tests. Among 254 potential coding sequences, the most comprehensive gene data set of eutherian Mas-related G protein-coupled receptor genes included 119 complete coding sequences that described eight major gene clusters. The present analysis integrated gene annotations, phylogenetic analysis and protein molecular evolution analysis and first explained differential gene expansion patterns of eutherian Mas-related G protein-coupled receptor genes. The updated classification and nomenclature of eutherian Mas-related G protein-coupled receptor genes were proposed as new framework of future experiments.