Promoter Complexity and Tissue-Specific Expression of Stress Response Components in Mytilus galloprovincialis, a Sessile Marine Invertebrate Species

The mechanisms of stress tolerance in sessile animals, such as molluscs, can offer fundamental insights into the adaptation of organisms for a wide range of environmental challenges. One of the best studied processes at the molecular level relevant to stress tolerance is the heat shock response in the genus Mytilus. We focus on the upstream region of Mytilus galloprovincialis Hsp90 genes and their structural and functional associations, using comparative genomics and network inference. Sequence comparison of this region provides novel evidence that the transcription of Hsp90 is regulated via a dense region of transcription factor binding sites, also containing a region with similarity to the Gamera family of LINE-like repetitive sequences and a genus-specific element of unknown function. Furthermore, we infer a set of gene networks from tissue-specific expression data, and specifically extract an Hsp class-associated network, with 174 genes and 2,226 associations, exhibiting a complex pattern of expression across multiple tissue types. Our results (i) suggest that the heat shock response in the genus Mytilus is regulated by an unexpectedly complex upstream region, and (ii) provide new directions for the use of the heat shock process as a biosensor system for environmental monitoring

The Complete Mitochondrial Genome of Bactrocera carambolae (Diptera: Tephritidae): Genome Description and Phylogenetic Implications

Bactrocera carambolae is one of the approximately 100 sibling species of the Bactrocera dorsalis complex and considered to be very closely related to B. dorsalis. Due to their high morphological similarity and overlapping distribution, as well as to their economic impact and quarantine status, the development of reliable markers for species delimitation between the two taxa is of great importance. Here we present the complete mitochondrial genome of B. carambolae sourced from its native range in Malaysia and its invaded territory in Suriname. The mitogenome of B. carambolae presents the typical organization of an insect mitochondrion. Comparisons of the analyzed B. carambolae sequences to all available complete mitochondrial sequences of B. dorsalis revealed several species-specific polymorphic sites. Phylogenetic analysis based on Bactrocera mitogenomes supports that B. carambolae is a differentiated taxon though closely related to B. dorsalis. The present complete mitochondrial sequences of B. carambolae could be used, in the frame of Integrative Taxonomy, for species discrimination and resolution of the phylogenetic relationships within this taxonomically challenging complex, which would facilitate the application of species-specific population suppression strategies, such as the sterile insect technique

Bayesian inference phylogenetic tree based on Hsp90 protein sequences from Chordata.

<p>Species in which multiple <i>hsp90</i> genes have been detected are in dark blue. Filled diamonds denote putative species-specific duplication events, predicted by this study. Filled square denotes the duplication event resulting in the cognate and inducible isoforms of vertebrates. Numbers at nodes represent Posterior Probability (PP) values. Scale bar: substitutions/site.</p

Assessment and Reconstruction of Novel HSP90 Genes: Duplications, Gains and Losses in Fungal and Animal Lineages

<div><p>Hsp90s, members of the Heat Shock Protein class, protect the structure and function of proteins and play a significant task in cellular homeostasis and signal transduction. In order to determine the number of <i>hsp90</i> gene copies and encoded proteins in fungal and animal lineages and through that key duplication events that this family has undergone, we collected and evaluated Hsp90 protein sequences and corresponding Expressed Sequence Tags and analyzed available genomes from various taxa. We provide evidence for duplication events affecting either single species or wider taxonomic groups. With regard to Fungi, duplicated genes have been detected in several lineages. In invertebrates, we demonstrate key duplication events in certain clades of Arthropoda and Mollusca, and a possible gene loss event in a hymenopteran family. Finally, we infer that the duplication event responsible for the two (a and b) isoforms in vertebrates occurred probably shortly after the split of Hyperoartia and Gnathostomata.</p></div

Bayesian inference phylogenetic tree based on Hsp90 protein sequences from Mollusca.

<p>Species in which multiple <i>hsp90</i> genes have been detected are in dark blue. Filled diamonds denote putative species-specific duplication events, predicted by this study. Numbers at nodes represent Posterior Probability (PP) values. Scale bar: substitutions/site.</p

Bayesian inference phylogenetic tree based on Hsp90 protein sequences from Fungi.

<p>Species in which multiple <i>hsp90</i> genes have been detected are in dark blue. Filled diamonds denote putative species-specific duplication events, predicted by this study. Stars represent whole-genome duplications reported by previous studies. Numbers at nodes represent Posterior Probability (PP) values. Scale bar: substitutions/site.</p

Bayesian inference phylogenetic tree based on Hsp90 protein sequences from Arthropoda.

<p>Species in which multiple <i>hsp90</i> genes have been detected are in dark blue. Filled diamonds denote putative species-specific duplication events predicted by this study. Filled squares denote duplication events in the common ancestor of a wide taxonomic group (e.g. Pleocyemata), predicted by this study. Filled circle shows the gain of type 2 isoform in Hymenoptera; empty-strikethrough circle shows loss of type 1 isoform in Formicidae. Numbers at nodes represent Posterior Probability (PP) values. Scale bar: substitutions/site.</p

Species distribution of BoR300 repeats.

<p>HaeIII-digested genomic DNA of representative species of the Diptera family and the genus Bactrocera was analyzed by Southern hybridization using as probe the biotinylated monomer (298 bp) of the repeat. (<b>A</b>) Southern blot analysis of digested genomic DNA from the following dipteran species: <i>B. oleae</i> (lane 1), <i>C. capitata</i> (lane 2), <i>D. melanogaster</i> (lane 3) and <i>An. gambiae</i> (lane 4). <b>B</b>) Southern blot analysis of digested genomic DNA from the following Bactrocera species: <i>B. oleae</i> (lane 1), <i>B. correcta</i> (lane 3), <i>B. cucurbitae</i> (lane 4), and <i>B. dorsalis</i> (lane 5). In Lane 2 is the cloned monomer of the repeat. M represents the molecular marker (SM0331, Fermentas).</p