Search results for "Multigene"
showing 10 items of 145 documents
Partial Sequence Homogenization in the 5S Multigene Families May Generate Sequence Chimeras and Spurious Results in Phylogenetic Reconstructions
2014
Multigene families have provided opportunities for evolutionary biologists to assess molecular evolution processes and phylogenetic reconstructions at deep and shallow systematic levels. However, the use of these markers is not free of technical and analytical challenges. Many evolutionary studies that used the nuclear 5S rDNA gene family rarely used contiguous 5S coding sequences due to the routine use of head-to-tail polymerase chain reaction primers that are anchored to the coding region. Moreover, the 5S coding sequences have been concatenated with independent, adjacent gene units in many studies, creating simulated chimeric genes as the raw data for evolutionary analysis. This practice…
Evolutionary conservation and function of the human embryonic stem cell specific miR-302/367 cluster
2015
miRNA clusters define a group of related miRNAs closely localized in the genome with an evolution that remains poorly understood. The miR-302/367 cluster represents a single polycistronic transcript that produces five precursor miRNAs. The cluster is highly expressed and essential for maintenance of human embryonic stem cells. We found the cluster to be highly conserved and present in most mammals. In primates, seed sequence and miRNA structure are conserved, but inter-precursor sequences are evolving. Insertions of new miRNAs, deletions of individual miRNAs, and a cluster duplication observed in different species suggest an actively evolving cluster. Core transcriptional machinery consisti…
Genetic variation of the interleukin-1 family and nongenetic factors determining the interleukin-1 receptor antagonist phenotypes.
2009
The natural anti-inflammatory protein interleukin-1 receptor antagonist (IL-1Ra) inhibits the activity of IL-1 and is associated with vascular injury and metabolic disorders. We analyzed genetic and nongenetic determinants of the IL-1Ra phenotype. Fifteen haplotype-tagging single nucleotide polymorphisms (SNPs) in the IL-1α (IL1A), IL-1β (IL1B), and IL-1 receptor antagonist (IL-1RN) genes were determined in the Health 2000 survey (n = 6771) and European myocardial infarction (MI) survivors (n = 972). Three SNPs were genotyped in the FINRISK97 (FR97) study (n = 7222). We found 3 IL1RN variants that were associated with the IL-1Ra phenotype in the study populations and remained significant af…
Tracing the origin of the compensasome: evolutionary history of DEAH helicase and MYST acetyltransferase gene families.
2001
Dosage compensation in Drosophila is mediated by a complex of proteins and RNAs called the "compensasome." Two of the genes that encode proteins of the complex, maleless (mle) and males-absent-on-the-first (mof), respectively, belong to the DEAH helicase and MYST acetyltransferase gene families. We performed comprehensive phylogenetic and structural analyses to determine the evolutionary histories of these two gene families and thus to better understand the origin of the compensasome. All of the members of the DEAH and MYST families of the completely sequenced Saccharomyces cerevisiae and Caenorhabditis elegans genomes, as well as those so far (June 2000) found in Drosophila melanogaster (f…
Multiple Ig-like featuring genes divergent within and among individuals of the marine sponge Geodia cydonium.
1998
Abstract The receptor tyrosine kinase of the marine sponge Geodia cydonium features two extracellular Ig-like domains in which we recently documented RT-PCR polymorphism among individuals. Genomic-PCR analysis presented here revealed 14 unique sequences from four sponges, differing predominantly in the sequence of an intron which splits the Ig-like domains. Nevertheless, analysis of putative coding regions in 19 distinct clones (156–159 aa) from seven sponges revealed 69 positions of nucleotide substitutions, 67.6% of them non-synonymous, translating into 43 positions of divergent residues. Excluding aa deletions, these 19 sequences share pairwise aa identities of 89–99%. In three sponges, …
Evolutionary and transcriptional analyses of a pentraxin-like component family involved in the LPS inflammatory response of Ciona robusta
2020
Pentraxins (PTXs) are a superfamily of conserved proteins which are components of the humoral arm of innate immunity. They are considered to be functional ancestors of antibodies and are classified into short and long types. In this study, we show that a pentraxin-like component (Ptx-like) with a C-terminal PTX domain, highly homologous to the short PTX of H. sapiens CRP, and a long N-terminal domain typical of long PTXs, is involved in the inflammatory response of Ciona robusta under LPS exposure in vivo. Analyses of protein domains as well as 3D modelling and phylogenetic tree supported the close relationship of Ptx-like with mammalian CRP, suggesting that C. robusta Ptx-like shares a com…
GSK-3 in liver diseases: Friend or foe?
2020
Liver diseases, including hepatitis due to hepatitis B or C virus infection, non-alcoholic fatty liver disease, and hepatocellular carcinoma pose major challenges for overall health due to limited curative treatment options. Thus, there is an urgent need to develop new therapeutic strategies for the treatment of these diseases. A better understanding of the signaling pathways involved in the pathogenesis of liver diseases can help to improve the efficacy of emerging therapies, mainly based on pharmacological approaches, which influence one or more specific molecules involved in key signal transduction pathways. These emerging therapies are very promising for the prevention and treatment of …
PCR survey ofXenoturbella bockiHox genes
2007
Xenoturbella bocki has recently been identified as one of the most basal deuterostomes, although an even more basal phylogenetic position cannot be ruled out. Here we report on a polymerase chain reaction survey of partial Hox homeobox sequences of X. bocki. Surprisingly, we did not find evidence for more than five Hox genes, one clear labial/PG1 ortholog, one posterior gene most similar to the PG9/10 genes of Ambulacraria, and three central group genes whose precise assignment to a specific paralog group remains open. We furthermore report on a re-evaluation of the available published evidence of Hox genes in other basal deuterostomes.
Respiratory proteins in Sipunculus nudus--implications for phylogeny and evolution of the hemerythrin family.
2009
Three major classes of respiratory proteins are known, hemoglobin, molluscan and arthropod hemocyanin, and hemerythrin (Hr). Similar to hemoglobin, respiratory Hr is packed into erythrocytes floating in the coelomic fluid and is only known from sipunculids, brachiopods, and priapulids. Owing to this scattered distribution, the presence of Hr is generally assumed to be the plesiomorphic condition without phylogenetic importance. By sequencing 2000 Expressed Sequence Tags (ESTs) from Sipunculus nudus, we found 75 Hr-coding ESTs assembled to 20 cDNA contigs classified as four distinct Hr isoforms: three polymeric Hrs (subunit A, A', and B) and the monomeric myo-hemerythrin (myoHr). Phylogeneti…
Formally described species woefully underrepresent phylogenetic diversity in the common lichen photobiont genus Trebouxia (Trebouxiophyceae, Chloroph…
2020
Lichens provide valuable systems for studying symbiotic interactions. In lichens, these interactions are frequently described in terms of availability, selectivity and specificity of the mycobionts and photobionts towards one another. The lichen-forming, green algal genus Trebouxia Puymaly is among the most widespread photobiont, associating with a broad range of lichen-forming fungi. To date, 29 species have been described, but studies consistently indicate that the vast majority of species-level lineages still lack formal description, and new, previously unrecognized lineages are frequently reported. To reappraise the diversity and the evolutionary relationships of species-level lineages …