scholarly journals The complex evolution of the HSP70 gene family

2020 ◽  
Author(s):  
Er-meng Yu ◽  
Tatsuki Yoshinaga ◽  
Frank L. Jalufka ◽  
Hashimul Ehsan ◽  
David B. Mark Welch ◽  
...  

AbstractThe 70-kDa heat shock protein (HSP70) family contains several isoforms localized in different subcellular compartments. The cytosolic isoforms have been classified into stress-inducible HSP70s and constitutive heat shock cognates (HSC70s), but occasional reports of “constitutive HSP70s” and the lack of cross-phylum comparisons have been a source of confusion in the evolution of the metazoan HSP70 family. Here we provide novel insights into the evolutionary history of this important molecular chaperone. We first cloned two HSP70 genes from the rotifer Brachionus plicatilis, an emerging model in evolutionary genetics, and confirmed their stress inducibility. Subsequent phylogenetic analyses of 100 full-length HSP70 family member genes revealed an ancient duplication that gave rise to two lineages from which all metazoan cytosolic HSP70s descend. One lineage contains a relatively small number of Lophotrochozoan and Ecdysozoan genes, none of which have been shown to be constitutively expressed. The second included both inducible and constitutive genes from diverse phyla. Species-specific duplications are present in both lineages, and in the second there are well-supported phylum-specific clades for Rotifera, Nematoda, and Chordata. Some genes in this lineage have likely independently acquired stress inducibility, which may explain the sporadic distribution of genes designated as “HSP70” or “HSC70” in previous analyses. Consistent with the history of diversification within each group, stress-inducible members of the second lineage show lower purifying selection pressure compared to constitutive members. These results illustrate the evolutionary history of the HSP70 family independent from their expression patterns, encouraging the development of new nomenclature based on evolutionary history.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Er-meng Yu ◽  
Tatsuki Yoshinaga ◽  
Frank L. Jalufka ◽  
Hashimul Ehsan ◽  
David B. Mark Welch ◽  
...  

AbstractThe metazoan 70-kDa heat shock protein (HSP70) family contains several members localized in different subcellular compartments. The cytosolic members have been classified into inducible HSP70s and constitutive heat shock cognates (HSC70s), but their distinction and evolutionary relationship remain unclear because of occasional reports of “constitutive HSP70s” and the lack of cross-phylum comparisons. Here we provide novel insights into the evolution of these important molecular chaperones. Phylogenetic analyses of 125 full-length HSP70s from a broad range of phyla revealed an ancient duplication that gave rise to two lineages from which all metazoan cytosolic HSP70s descend. One lineage (A) contains a relatively small number of genes from many invertebrate phyla, none of which have been shown to be constitutively expressed (i.e., either inducible or unknown). The other lineage (B) included both inducible and constitutive genes from diverse phyla. Species-specific duplications are present in both lineages, and Lineage B contains well-supported phylum-specific clades for Platyhelminthes, Rotifera, Nematoda, Porifera/Cnidaria, and Chordata. Some genes in Lineage B have likely independently acquired inducibility, which may explain the sporadic distribution of “HSP70” or “HSC70” in previous phylogenetic analyses. Consistent with the diversification history within each group, inducible members show lower purifying selection pressure compared to constitutive members. These results illustrate the evolutionary history of the HSP70 family, encouraging us to propose a new nomenclature: “HSP70 + subcellular localization + linage + copy number in the organism + inducible or constitutive, if known.” e.g., HSP70cA1i for cytosolic Lineage A, copy 1, inducible.


2019 ◽  
Vol 286 (1897) ◽  
pp. 20182929 ◽  
Author(s):  
Elena A. Ritschard ◽  
Robert R. Fitak ◽  
Oleg Simakov ◽  
Sönke Johnsen

Coleoid cephalopods show unique morphological and neural novelties, such as arms with tactile and chemosensory suckers and a large complex nervous system. The evolution of such cephalopod novelties has been attributed at a genomic level to independent gene family expansions, yet the exact association and the evolutionary timing remain unclear. In the octopus genome, one such expansion occurred in the G-protein-coupled receptors (GPCRs) repertoire, a superfamily of proteins that mediate signal transduction. Here, we assessed the evolutionary history of this expansion and its relationship with cephalopod novelties. Using phylogenetic analyses, at least two cephalopod- and two octopus-specific GPCR expansions were identified. Signatures of positive selection were analysed within the four groups, and the locations of these sequences in the Octopus bimaculoides genome were inspected. Additionally, the expression profiles of cephalopod GPCRs across various tissues were extracted from available transcriptomic data. Our results reveal the evolutionary history of cephalopod GPCRs. Unexpanded cephalopod GPCRs shared with other bilaterians were found to be mainly nervous tissue specific. By contrast, duplications that are shared between octopus and the bobtail squid or specific to the octopus' lineage generated copies with divergent expression patterns devoted to tissues outside of the brain. The acquisition of novel expression domains was accompanied by gene order rearrangement through either translocation or duplication and gene loss. Lastly, expansions showed signs of positive selection and some were found to form tandem clusters with shared conserved expression profiles in cephalopod innovations such as the axial nerve cord. Altogether, our results contribute to the understanding of the molecular and evolutionary history of signal transduction and provide insights into the role of this expansion during the emergence of cephalopod novelties and/or adaptations.


Viruses ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 641 ◽  
Author(s):  
Pakorn Aiewsakun ◽  
Peter Simmonds ◽  
Aris Katzourakis

A recent study reported the discovery of an endogenous reptilian foamy virus (FV), termed ERV-Spuma-Spu, found in the genome of tuatara. Here, we report two novel reptilian foamy viruses also identified as endogenous FVs (EFVs) in the genomes of panther gecko (ERV-Spuma-Ppi) and Schlegel’s Japanese gecko (ERV-Spuma-Gja). Their presence indicates that FVs are capable of infecting reptiles in addition to mammals, amphibians, and fish. Numerous copies of full length ERV-Spuma-Spu elements were found in the tuatara genome littered with in-frame stop codons and transposable elements, suggesting that they are indeed endogenous and are not functional. ERV-Spuma-Ppi and ERV-Spuma-Gja, on the other hand, consist solely of a foamy virus-like env gene. Examination of host flanking sequences revealed that they are orthologous, and despite being more than 96 million years old, their env reading frames are fully coding competent with evidence for strong purifying selection to maintain expression and for them likely being transcriptionally active. These make them the oldest EFVs discovered thus far and the first documented EFVs that may have been co-opted for potential cellular functions. Phylogenetic analyses revealed a complex virus–host co-evolutionary history and cross-species transmission routes of ancient FVs.


2019 ◽  
Vol 12 (1) ◽  
pp. 3615-3634 ◽  
Author(s):  
Guangshuai Liu ◽  
Huanxin Zhang ◽  
Chao Zhao ◽  
Honghai Zhang

Abstract Adaptation to a wide range of pathogenic environments is a major aspect of the ecological adaptations of vertebrates during evolution. Toll-like receptors (TLRs) are ancient membrane-bound sensors in animals and are best known for their roles in detecting and defense against invading pathogenic microorganisms. To understand the evolutionary history of the vertebrate TLR gene family, we first traced the origin of single-cysteine cluster TLRs that share the same protein architecture with vertebrate TLRs in early-branching animals and then analyzed all members of the TLR family in over 200 species covering all major vertebrate clades. Our results indicate that although the emergence of single-cysteine cluster TLRs predates the separation of bilaterians and cnidarians, most vertebrate TLR members originated shortly after vertebrate emergence. Phylogenetic analyses divided 1,726 vertebrate TLRs into 8 subfamilies, and TLR3 may represent the most ancient subfamily that emerged before the branching of deuterostomes. Our analysis reveals that purifying selection predominated in the evolution of all vertebrate TLRs, with mean dN/dS (ω) values ranging from 0.082 for TLR21 in birds to 0.434 for TLR11 in mammals. However, we did observe patterns of positive selection acting on specific codons (527 of 60,294 codons across all vertebrate TLRs, 8.7‰), which are significantly concentrated in ligand-binding extracellular domains and suggest host–pathogen coevolutionary interactions. Additionally, we found stronger positive selection acting on nonviral compared with viral TLRs, indicating the more essential nonredundant function of viral TLRs in host immunity. Taken together, our findings provide comprehensive insight into the complex evolutionary processes of the vertebrate TLR gene family, involving gene duplication, pseudogenization, purification, and positive selection.


Author(s):  
Sergio A Muñoz-Gómez ◽  
Keira Durnin ◽  
Laura Eme ◽  
Christopher Paight ◽  
Christopher E Lane ◽  
...  

Abstract A most interesting exception within the parasitic Apicomplexa is Nephromyces, an extracellular, probably mutualistic, endosymbiont found living inside molgulid ascidian tunicates (i.e., sea squirts). Even though Nephromyces is now known to be an apicomplexan, many other questions about its nature remain unanswered. To gain further insights into the biology and evolutionary history of this unusual apicomplexan, we aimed to (1) find the precise phylogenetic position of Nephromyces within the Apicomplexa, (2) search for the apicoplast genome of Nephromyces, and (3) infer the major metabolic pathways in the apicoplast of Nephromyces. To do this, we sequenced a metagenome and a metatranscriptome from the molgulid renal sac, the specialized habitat where Nephromyces thrives. Our phylogenetic analyses of conserved nucleus-encoded genes robustly suggest that Nephromyces is a novel lineage sister to the Hematozoa, which comprises both the Haemosporidia (e.g., Plasmodium) and the Piroplasmida (e.g., Babesia and Theileria). Furthermore, a survey of the renal sac metagenome revealed 13 small contigs that closely resemble the genomes of the non-photosynthetic reduced plastids, or apicoplasts, of other apicomplexans. We show that these apicoplast genomes correspond to a diverse set of most closely related but genetically divergent Nephromyces lineages that co-inhabit a single tunicate host. In addition, the apicoplast of Nephromyces appears to have retained all biosynthetic pathways inferred to have been ancestral to parasitic apicomplexans. Our results shed light on the evolutionary history of the only probably mutualistic apicomplexan known, Nephromyces, and provide context for a better understanding of its life style and intricate symbiosis.


2021 ◽  
Author(s):  
Caitlin Cherryh ◽  
Bui Quang Minh ◽  
Rob Lanfear

AbstractMost phylogenetic analyses assume that the evolutionary history of an alignment (either that of a single locus, or of multiple concatenated loci) can be described by a single bifurcating tree, the so-called the treelikeness assumption. Treelikeness can be violated by biological events such as recombination, introgression, or incomplete lineage sorting, and by systematic errors in phylogenetic analyses. The incorrect assumption of treelikeness may then mislead phylogenetic inferences. To quantify and test for treelikeness in alignments, we develop a test statistic which we call the tree proportion. This statistic quantifies the proportion of the edge weights in a phylogenetic network that are represented in a bifurcating phylogenetic tree of the same alignment. We extend this statistic to a statistical test of treelikeness using a parametric bootstrap. We use extensive simulations to compare tree proportion to a range of related approaches. We show that tree proportion successfully identifies non-treelikeness in a wide range of simulation scenarios, and discuss its strengths and weaknesses compared to other approaches. The power of the tree-proportion test to reject non-treelike alignments can be lower than some other approaches, but these approaches tend to be limited in their scope and/or the ease with which they can be interpreted. Our recommendation is to test treelikeness of sequence alignments with both tree proportion and mosaic methods such as 3Seq. The scripts necessary to replicate this study are available at https://github.com/caitlinch/treelikeness


2021 ◽  
Author(s):  
Keerthic Aswin ◽  
Srinivasan Ramachandran ◽  
Vivek T Natarajan

AbstractEvolutionary history of coronaviruses holds the key to understand mutational behavior and prepare for possible future outbreaks. By performing comparative genome analysis of nidovirales that contain the family of coronaviruses, we traced the origin of proofreading, surprisingly to the eukaryotic antiviral component ZNFX1. This common recent ancestor contributes two zinc finger (ZnF) motifs that are unique to viral exonuclease, segregating them from DNA proof-readers. Phylogenetic analyses indicate that following acquisition, genomes of coronaviruses retained and further fine-tuned proofreading exonuclease, whereas related families harbor substitution of key residues in ZnF1 motif concomitant to a reduction in their genome sizes. Structural modelling followed by simulation suggests the role of ZnF in RNA binding. Key ZnF residues strongly coevolve with replicase, and the helicase involved in duplex RNA unwinding. Hence, fidelity of replication in coronaviruses is a result of convergent evolution, that enables maintenance of genome stability akin to cellular proofreading systems.


2020 ◽  
Vol 21 (2) ◽  
pp. 513 ◽  
Author(s):  
Marzia Tindara Venuto ◽  
Mathieu Decloquement ◽  
Joan Martorell Ribera ◽  
Maxence Noel ◽  
Alexander Rebl ◽  
...  

We identified and analyzed α2,8-sialyltransferases sequences among 71 ray-finned fish species to provide the first comprehensive view of the Teleost ST8Sia repertoire. This repertoire expanded over the course of Vertebrate evolution and was primarily shaped by the whole genome events R1 and R2, but not by the Teleost-specific R3. We showed that duplicated st8sia genes like st8sia7, st8sia8, and st8sia9 have disappeared from Tetrapods, whereas their orthologues were maintained in Teleosts. Furthermore, several fish species specific genome duplications account for the presence of multiple poly-α2,8-sialyltransferases in the Salmonidae (ST8Sia II-r1 and ST8Sia II-r2) and in Cyprinus carpio (ST8Sia IV-r1 and ST8Sia IV-r2). Paralogy and synteny analyses provided more relevant and solid information that enabled us to reconstruct the evolutionary history of st8sia genes in fish genomes. Our data also indicated that, while the mammalian ST8Sia family is comprised of six subfamilies forming di-, oligo-, or polymers of α2,8-linked sialic acids, the fish ST8Sia family, amounting to a total of 10 genes in fish, appears to be much more diverse and shows a patchy distribution among fish species. A focus on Salmonidae showed that (i) the two copies of st8sia2 genes have overall contrasted tissue-specific expressions, with noticeable changes when compared with human co-orthologue, and that (ii) st8sia4 is weakly expressed. Multiple sequence alignments enabled us to detect changes in the conserved polysialyltransferase domain (PSTD) of the fish sequences that could account for variable enzymatic activities. These data provide the bases for further functional studies using recombinant enzymes.


2020 ◽  
Vol 21 (2) ◽  
pp. 608 ◽  
Author(s):  
Jiali Ye ◽  
Xuetong Yang ◽  
Gan Hu ◽  
Qi Liu ◽  
Wei Li ◽  
...  

Heat shock transcription factors (HSFs) play crucial roles in resisting heat stress and regulating plant development. Recently, HSFs have been shown to play roles in anther development. Thus, investigating the HSF family members and identifying their protective roles in anthers are essential for the further development of male sterile wheat breeding. In the present study, 61 wheat HSF genes (TaHsfs) were identified in the whole wheat genome and they are unequally distributed on 21 chromosomes. According to gene structure and phylogenetic analyses, the 61 TaHsfs were classified into three categories and 12 subclasses. Genome-wide duplication was identified as the main source of the expansion of the wheat HSF gene family based on 14 pairs of homeologous triplets, whereas only a very small number of TaHsfs were derived by segmental duplication and tandem duplication. Heat shock protein 90 (HSP90), HSP70, and another class of chaperone protein called htpG were identified as proteins that interact with wheat HSFs. RNA-seq analysis indicated that TaHsfs have obvious period- and tissue-specific expression patterns, and the TaHsfs in classes A and B respond to heat shock, whereas the C class TaHsfs are involved in drought regulation. qRT-PCR identified three TaHsfA2bs with differential expression in sterile and fertile anthers, and they may be candidate genes involved in anther development. This comprehensive analysis provides novel insights into TaHsfs, and it will be useful for understanding the mechanism of plant fertility conversion.


2002 ◽  
Vol 93 (4) ◽  
pp. 333-353 ◽  
Author(s):  
Julia J. Day

ABSTRACTThe Eocene sparid fauna (Teleostei: Percoidei) from Monte Bolca, Italy and from the London Clay, U.K. is revised based on re-examination of the type material and phylogenetic analyses of primarily osteological data. Two phylogenetic analyses, one of the Eocene taxa and a combined analysis of fossil and extant taxa, were performed. The addition of fossils to the extant data greatly increased numbers of most parsimonious trees, destabilising and obscuring basal relationships within the Sparidae. Combination of the data from fossil and extant data also affected relationships among the fossil taxa, changing some from those recovered using fossil data alone and destabilising others. Successive approximations character weighting supported the inclusion of the Eocene taxa within a monophyletic Sparidae. The genus Sparnodus, as previously conceived, is paraphyletic and is partitioned to remove the paraphyly. Five monotypic genera are recognised, including three new genera, Abromasta, Ellaserrata and Pseudosparnodus. Inclusion of the fossils in the phylogenetic analysis implies a minimum age of origin for the Sparidae of 55 Ma with most Recent sparid fauna in place no later than the Miocene, and provides further evidence that the diversification of feeding strategies occurred early on in the evolutionary history of the group.


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