@article {554, title = {The genome and adult somatic transcriptome of the mormyrid electric fish Paramormyrops kingsleyae}, journal = {Genome Biology and Evolution}, year = {2017}, month = {Dec-12-2017}, abstract = {

Several studies have begun to elucidate the genetic and developmental processes underlying major vertebrate traits. Few of these traits have evolved repeatedly in vertebrates, preventing the analysis of molecular mechanisms underlying these traits comparatively. Electric organs have evolved multiple times among vertebrates, presenting a unique opportunity to understand the degree of constraint and repeatability of the evolutionary processes underlying novel vertebrate traits. As there is now a completed genome sequence representing south american electric eels, we were motivated to obtain genomic sequence from a linage that independently evolved electric organs to facilitate future comparative analyses of the evolution and development of electric organs. We report here the sequencing and de-novo assembly of the genome of the mormyrid Paramormyrops kingsleyae using short-read sequencing. In addition, we have completed a somatic transcriptome from 11 tissues to construct a gene expression atlas of predicted genes from this assembly, enabling us to identify candidate housekeeping genes as well as genes differentially expressed in the major somatic tissues of the mormyrid electric fish. We anticipate that this resource will greatly facilitate comparative studies on the evolution and development of electric organs and electroreceptors.

}, doi = {10.1093/gbe/evx265}, url = {http://academic.oup.com/gbe/advance-article/doi/10.1093/gbe/evx265/4731783}, author = {Jason R. Gallant and Losilla, Mauricio and Tomlinson, Chad and Warren, Wesley C} } @article {836, title = {Differential expression of genes and proteins between electric organ and skeletal muscle in the mormyrid electric fish Brienomyrus brachyistius}, journal = {Journal of Experimental Biology}, volume = {215}, year = {2012}, month = {07/2012}, pages = {2479 - 2494}, abstract = {

Electric organs (EOs) have evolved independently in vertebrates six times from skeletal muscle (SM). The transcriptional changes accompanying this developmental transformation are not presently well understood. Mormyrids and gymnotiforms are two highly convergent groups of weakly electric fish that have independently evolved EOs: while much is known about development and gene expression in gymnotiforms, very little is known about development and gene expression in mormyrids. This lack of data limits prospects for comparative work. We report here on the characterization of 28 differentially expressed genes between SM and EO tissues in the mormyrid Brienomyrus brachyistius, which were identified using suppressive subtractive hybridization (SSH). Forward and reverse SSH was performed on tissue samples of EO and SM resulting in one cDNA library enriched with mRNAs expressed in EO, and a second library representing mRNAs unique to SM. Nineteen expressed sequence tags (ESTs) were identified in EO and nine were identified in SM using BLAST searching of Danio rerio sequences available in NCBI databases. We confirmed differential expression of all 28 ESTs using RT-PCR. In EO, these ESTs represent four classes of proteins: (1) ion pumps, including the - and -subunits of Na+/K+-ATPase, and a plasma membrane Ca2+-ATPase; (2) Ca2+-binding protein S100, several parvalbumin paralogs, calcyclin-binding protein and neurogranin; (3) sarcomeric proteins troponin I, myosin heavy chain and actin-related protein complex subunit 3 (Arcp3); and (4) the transcription factors enhancer of rudimentary homolog (ERH) and myocyte enhancer factor 2A (MEF2A). Immunohistochemistry and western blotting were used to demonstrate the translation of seven proteins (myosin heavy chain, Na+/K+-ATPase, plasma membrane Ca2+-ATPase, MEF2, troponin and parvalbumin) and their cellular localization in EO and SM. Our findings suggest that mormyrids express several paralogs of muscle-specific genes and the proteins they encode in EOs, unlike gymnotiforms, which may post-transcriptionally repress several sarcomeric proteins. In spite of the similarity in the physiology and function of EOs in mormyrids and gymnotiforms, this study indicates that the mechanisms of development in the two groups may be considerably different.

}, issn = {1477-9145}, doi = {10.1242/jeb.063222}, author = {Jason R. Gallant and Carl D. Hopkins and Deitcher, D. L.} } @article {853, title = {Differential expression of genes and proteins between electric organ and skeletal muscle in the mormyrid electric fish Brienomyrus brachyistius}, journal = {Journal of Experimental Biology}, volume = {215}, year = {2012}, month = {07/2012}, pages = {2479 - 2494}, abstract = {

Electric organs (EOs) have evolved independently in vertebrates six times from skeletal muscle (SM). The transcriptional changes accompanying this developmental transformation are not presently well understood. Mormyrids and gymnotiforms are two highly convergent groups of weakly electric fish that have independently evolved EOs: while much is known about development and gene expression in gymnotiforms, very little is known about development and gene expression in mormyrids. This lack of data limits prospects for comparative work. We report here on the characterization of 28 differentially expressed genes between SM and EO tissues in the mormyrid Brienomyrus brachyistius, which were identified using suppressive subtractive hybridization (SSH). Forward and reverse SSH was performed on tissue samples of EO and SM resulting in one cDNA library enriched with mRNAs expressed in EO, and a second library representing mRNAs unique to SM. Nineteen expressed sequence tags (ESTs) were identified in EO and nine were identified in SM using BLAST searching of Danio rerio sequences available in NCBI databases. We confirmed differential expression of all 28 ESTs using RT-PCR. In EO, these ESTs represent four classes of proteins: (1) ion pumps, including the \α- and \β-subunits of Na(+)/K(+)-ATPase, and a plasma membrane Ca(2+)-ATPase; (2) Ca(2+)-binding protein S100, several parvalbumin paralogs, calcyclin-binding protein and neurogranin; (3) sarcomeric proteins troponin I, myosin heavy chain and actin-related protein complex subunit 3 (Arcp3); and (4) the transcription factors enhancer of rudimentary homolog (ERH) and myocyte enhancer factor 2A (MEF2A). Immunohistochemistry and western blotting were used to demonstrate the translation of seven proteins (myosin heavy chain, Na(+)/K(+)-ATPase, plasma membrane Ca(2+)-ATPase, MEF2, troponin and parvalbumin) and their cellular localization in EO and SM. Our findings suggest that mormyrids express several paralogs of muscle-specific genes and the proteins they encode in EOs, unlike gymnotiforms, which may post-transcriptionally repress several sarcomeric proteins. In spite of the similarity in the physiology and function of EOs in mormyrids and gymnotiforms, this study indicates that the mechanisms of development in the two groups may be considerably different.

}, issn = {1477-9145}, doi = {10.1242/jeb.063222}, author = {Jason R. Gallant and Carl D. Hopkins and Deitcher, D. L.} }