Differential expression of the aryl hydrocarbon receptor pathway associates with craniofacial polymorphism in sympatric Arctic charr. Ahi EP, Steinhäuser SS, Pálsson A, Franzdóttir SR, Snorrason SS, Maier VH, Jónsson ZO. Evodevo. 2015 Sep 16;6:27. doi: 10.1186/s13227-015-0022-6.
BACKGROUND:
Just accepted in EvoDevo
Differential expression of the Aryl hydrocarbon receptor pathway associates with craniofacial polymorphism in sympatric Arctic charr
Ehsan Pashay Ahi; Sophie S Steinhäuser; Arnar Pálsson; Sigrídur Rut Franzdóttir; Sigurdur S Snorrason; Valerie Helene Maier, Zophonías O Jónsson
Im quite proud of helping with evolutionary and statistical analyses for a recent paper from Francesca Pignoni and colleagues.
Zhang T, Zhou Q, Ogmundsdottir MH, Möller K, Siddaway R, Larue L, Hsing M, Kong SW, Goding CR,
Palsson A, Steingrimsson E, Pignoni F.
Mitf is a master regulator of the v-ATPase, forming a control module for cellular homeostasis with v-ATPase and TORC1. J Cell Sci. 2015 Aug 1;128(15):2938-50. doi: 10.1242/jcs.173807. Epub 2015 Jun 19.
Abstract
The v-ATPase is a fundamental eukaryotic enzyme that is central to cellular homeostasis. Although its impact on key metabolic regulators such as TORC1 is well documented, our knowledge of mechanisms that regulate v-ATPase activity is limited. Here, we report that the Drosophila transcription factor Mitf is a master regulator of this holoenzyme. Mitf directly controls transcription of all 15 v-ATPase components through M-box cis-sites and this coordinated regulation affects holoenzyme activity in vivo. In addition, through the v-ATPase, Mitf promotes the activity of TORC1, which in turn negatively regulates Mitf. We provide evidence that Mitf, v-ATPase and TORC1 form a negative regulatory loop that maintains each of these important metabolic regulators in relative balance. Interestingly, direct regulation of v-ATPase genes by human MITF also occurs in cells of the melanocytic lineage, showing mechanistic conservation in the regulation of the v-ATPase by MITF family proteins in fly and mammals. Collectively, this evidence points to an ancient module comprising Mitf, v-ATPase and TORC1 that serves as a dynamic modulator of metabolism for cellular homeostasis.
Bones in motion: Ontogeny of craniofacial development in sympatric Arctic charr morphs
Kalina H. Kapralova, Zophonías O. Jónsson, Arnar Palsson, Sigrídur Rut Franzdóttir, Soizic Le Deuff, Bjarni K. Kristjanson, Sigurður S. Snorrason.
Background: The impressive diversity in the feeding apparatus often seen among related fish species clearly reflects differences in feeding modes and habitat utilization. Such variation can also be found within species. One example of such intraspecific diversity is the Arctic charr in Lake Thingvallavatn, where four distinct morphs coexist: two limnetic with evenly protruding jaws and two benthic with subterminal lower jaws. We used these recently evolved morphs to study the role of ontogenetic variation for craniofacial diversity. Continue reading 'Bones in motion: Ontogeny of craniofacial development in sympatric Arctic charr morphs - accepted in Developmental dynamics'»
Lets hope we are lucky third time around. Now we send this little baby to F1000research. The developmental transcriptome of contrasting Arctic charr (Salvelinus alpinus) morphs Johannes Gudbrandsson*, Ehsan P. Ahi, Sigridur R. Franzdottir, Kalina. H. Kapralova, Bjarni K. Kristjansson#, S. Sophie Steinhaeuser, Isak M. Johannesson, Valerie H. Maier, Sigurdur S. Snorrason, Zophonias O. Jonsson, and Arnar Palsson* Institute of Life and Environmental Sciences, University of Iceland, 101 Reykjavik, Iceland #Holar University College, 551 Saudarkrokur, Iceland *Corresponding authors.
Continue reading 'The developmental transcriptome of contrasting Arctic charr (Salvelinus alpinus) morphs - sent to F1000research'»
We just sent this manuscript to PLoS One, after G3 decided they did not like it. (Main sticking point is that they wanted de novo assembly - but we argued it was not a good idea with the 36bp non paired end reads) At any rate, I like PLoS One, and would like to publish one paper there a year...
Continue reading 'Submitted to Plos One: The developmental transcriptome of contrasting Arctic charr (Salvelinus alpinus) morphs'»
Sorry, this entry is only available in Icelandic.
Sorry, this entry is only available in Icelandic.
We just submitted a paper to G3, and deposited the manuscript on BioRxiv.
The developmental transcriptome of contrasting Arctic charr (Salvelinus alpinus) morphs
Jóhannes Gudbrandsson, Ehsan P Ahi, Kalina H Kapralova, Sigrídur R Franzdottir, Bjarni K Kristjánsson, Sophie S Steinhaeuser, Ísak M Jóhannesson, Valerie H Maier, Sigurdur S Snorrason, Zophonías O Jónsson, Arnar Pálsson
Species showing repeated evolution of similar traits can help illuminate the molecular and developmental basis of diverging traits and specific adaptations. Following the last glacial period, dwarfism and specialized bottom feeding morphology evolved rapidly in several landlocked Arctic charr (Salvelinus alpinus) populations in Iceland.
In order to study the genetic divergence between small benthic morphs and larger morphs with limnetic morphotype, we conducted an RNA-seq transcriptome analysis of developing charr. We sequenced mRNA from whole embryos at four stages in early development of two stocks with very different morphologies, the small benthic (SB) charr from Lake Thingvallavatn and Holar aquaculture (AC) charr. The data reveal significant differences in expression of several biological pathways during charr development. There is also a difference between SB- and AC-charr in mitochondrial genes involved in energy metabolism and blood coagulation genes. We confirmed expression difference of five genes in whole embryos with qPCR, including lysozyme and natterin which was previously identified as a fish-toxin of a lectin family that may be a putative immunopeptide. We verified differential expression of 7 genes in developing heads, and the expression associated consistently with benthic v.s. limnetic charr (studied in 4 morphs total). Comparison of Single nucleotide polymorphism (SNP) frequencies reveals extensive genetic differentiation between the SB- and AC-charr (60 fixed SNPs and around 1300 differing more than 50% in frequency). In SB-charr the high frequency derived SNPs are in genes related to translation and oxidative processes. Curiously, several derived SNPs reside in the 12s and 16s mitochondrial ribosomal RNA genes, including a base highly conserved among fishes.
The data implicate multiple genes and molecular pathways in divergence of small benthic charr and/or the response of aquaculture charr to domestication. Functional, genetic and population genetic studies on more freshwater and anadromous populations are needed to confirm the specific loci and mutations relating to specific ecological or domestication traits in Arctic charr.
