Examining Ari Jon Arasons thesis on bronchial stem cells

Arnar Pálsson, 31/01/2016

This Friday I enjoyed the privilege of being a Phd. examiner for the first time. The (un)fortunate individual was Ari Jon Arason, who has been working on the functional role of human bronchial derived basal cells in regeneration and fibrosis within the Faculty of medicine.

Emma Rawlins from the Gurdon Institute was the other examiner, and she did a marvelous job. She works in the field of stem cell biology and has a fabulously interesting paper on biophysical model of basal stem cell populations (Watson JK, Rulands S, Wilkinson AC, Wuidart A, Ousset M, Van Keymeulen A, Gottgens B, Blanpain C, Simons BD and Rawlins EL (2015) Clonal Dynamics Reveal Two Distinct Populations of Basal Cells in Slow Turnover Airway Epithelium. Cell Reports 12, 1-12)

After her questions all I could ask about was evolution of lungs, and stem cells and variation in lung structures between individuals, and transcription factor isoforms of course. All in all this was an enjoyable experience. The work was well executed and interesting, his thesis was a good read and corduroy gowns a lot less awful than I imagined. For some reason the University of Iceland has adopted very formal guidelines for PhD. defenses, involving gowns, parading and verbose introductions and declarations. At least the Rector does not have to sip champagne with every new Phd, as the earlier guidelines stipulated.

Eulogy for Sigridur H. Thorbjarnardottir

Arnar Pálsson, 07/01/2016

Sigridur Helga Thorbjarnardottir passed away late 2015. She was my main advisor during my master studies at the University of Iceland. The other advisor was Gudmundur Eggertsson. Sigridur was also the head of the Icelandic biological society in the eighties. The eulogy in icelandic appeared in the local paper and on the website of the society.

(Icelandic) Leyndardómar gena, baktería og uppruna lífs – ritrýni í Náttúrufræðingnum

Arnar Pálsson, 16/12/2015

Sorry, this entry is only available in Icelandic.

IceBio 2015

Arnar Pálsson, 23/11/2015

In the beginning of November the Icelandic biological society and associates organized a conference on biological research in Iceland. This event has run biannually since 2009, and before that it was organized by the society and the Institute of Biology at the University of Iceland (every 5 years).

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Published: Differential expression of the aryl hydrocarbon receptor pathway associates with craniofacial polymorphism in sympatric Arctic charr

Arnar Pálsson, 28/09/2015

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:

The developmental basis of craniofacial morphology hinges on interactions of numerous signalling systems. Extensive craniofacial variation in the polymorphic Arctic charr, a member of the salmonid family, from Lake Thingvallavatn (Iceland), offers opportunities to find and study such signalling pathways and their key regulators, thereby shedding light on the developmental pathways, and the genetics of trophic divergence.

Continue reading 'Published: Differential expression of the aryl hydrocarbon receptor pathway associates with craniofacial polymorphism in sympatric Arctic charr'»

(Icelandic) Minning um taugalíffræðingin Oliver Sacks

Arnar Pálsson, 28/09/2015

Sorry, this entry is only available in Icelandic.

Accepted: Differential expression of the Aryl hydrocarbon receptor pathway associates with craniofacial polymorphism in sympatric Arctic charr

Arnar Pálsson, 05/09/2015

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

Mitf is a master regulator of the v-ATPase, forming a control module for cellular homeostasis with v-ATPase and TORC1.

Arnar Pálsson, 05/08/2015
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.

Post doc available: The role of transcriptional and regulatory changes during compensatory evolution

Arnar Pálsson, 02/07/2015

Which principles influence the rewiring and tuning of gene regulatory networks? How do those network react to genetic perturbations? We are seeking a post-doc to tackle those and related questions in project utilizing populations of Drosophila (fruit flies) that have undergone compensatory adaptation using experimental evolution and artificial selection. The project involves the analysis of tissue specific RNA-seq and numerical analyses. The ideal candidate is strong in evolutionary genetics, statistical and bioinformatic analyses and with capable hands for molecular biology. Excellent communication skills, main focus on writing, are required, as is a solid publication record. The candidate will be encouraged (and given time) to develop their own research program.

This project is built on hypothesis that sprung out of work on indel polymorphism in the even skipped stripes 3+7 enhancer.

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Bones in motion: Ontogeny of craniofacial development in sympatric Arctic charr morphs – accepted in Developmental dynamics

Arnar Pálsson, 08/06/2015

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'»