- Seminars - maillist.psb.ugent.be

PSB event reminder
by contact＠psb.vib-ugent.be 24 Jan '13

24 Jan '13

Calendar Name: seminars Scheduled for: Thursday, January 24 2013, 11:00 - 12:30 Event text: Dr Steven Maere VIB, Dept. of Plant Systems Biology Ghent University Gent BELGIUM Details: �Innovation through gen(om)e duplication� ABSTRACT Gene and genome duplications are believed to facilitate evolutionary innovation. However, the mechanisms shaping the fate of duplicated genes remain heavily debated because the molecular processes and evolutionary forces involved are difficult to reconstruct. The first part of the talk will focus on the MALS gene family, a large family of fungal glucosidase genes with members generally having activity on only one of two broad substrate classes. We reconstructed several key ancestral enzymes and show that the very first preduplication enzyme was primarily active on maltose-like substrates, but had trace activity for isomaltose-like sugars. Structural analysis and activity measurements on resurrected and present-day enzymes suggest that both activities cannot be fully optimized in a single enzyme. However, gene duplications repeatedly spawned daughter genes in which mutations optimized either isomaltase or maltase activity. Interestingly, similar shifts in enzyme activity were reached multiple times via different evolutionary routes. Together, our results provide a detailed picture of the molecular mechanisms that drove divergence and innovation in the MALS gene family. In the second part of the talk, I will discuss a framework we developed for simulating the evolution of small biological systems in silico. The genotype-phenotype map (GPM) of any molecular system results from a highly multilayered information processing cascade, in which gene regulatory networks (GRNs) play a crucial role. Several simplifying mathematical representations of GPMs have been developed in the past. However, these representations generally lack biological realism in the genotypic encoding of the structure and parameters of GRNs. To study GPMs in mechanistic detail, we have developed a sequence-based dynamical modeling framework built upon biochemical first principles. As a proof of concept, we focus on genomes coding for small GRNs displaying oscillatory expression phenotypes. We show that genome duplication drastically impacts the navigability of the fitness landscape and the accessibility of novel phenotypes.

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PSB event reminder
by contact＠psb.vib-ugent.be 22 Jan '13

22 Jan '13

Calendar Name: seminars Scheduled for: Thursday, January 24 2013, 11:00 - 12:30 Event text: Dr Steven Maere VIB, Dept. of Plant Systems Biology Ghent University Gent BELGIUM Details: �Innovation through gen(om)e duplication� ABSTRACT Gene and genome duplications are believed to facilitate evolutionary innovation. However, the mechanisms shaping the fate of duplicated genes remain heavily debated because the molecular processes and evolutionary forces involved are difficult to reconstruct. The first part of the talk will focus on the MALS gene family, a large family of fungal glucosidase genes with members generally having activity on only one of two broad substrate classes. We reconstructed several key ancestral enzymes and show that the very first preduplication enzyme was primarily active on maltose-like substrates, but had trace activity for isomaltose-like sugars. Structural analysis and activity measurements on resurrected and present-day enzymes suggest that both activities cannot be fully optimized in a single enzyme. However, gene duplications repeatedly spawned daughter genes in which mutations optimized either isomaltase or maltase activity. Interestingly, similar shifts in enzyme activity were reached multiple times via different evolutionary routes. Together, our results provide a detailed picture of the molecular mechanisms that drove divergence and innovation in the MALS gene family. In the second part of the talk, I will discuss a framework we developed for simulating the evolution of small biological systems in silico. The genotype-phenotype map (GPM) of any molecular system results from a highly multilayered information processing cascade, in which gene regulatory networks (GRNs) play a crucial role. Several simplifying mathematical representations of GPMs have been developed in the past. However, these representations generally lack biological realism in the genotypic encoding of the structure and parameters of GRNs. To study GPMs in mechanistic detail, we have developed a sequence-based dynamical modeling framework built upon biochemical first principles. As a proof of concept, we focus on genomes coding for small GRNs displaying oscillatory expression phenotypes. We show that genome duplication drastically impacts the navigability of the fitness landscape and the accessibility of novel phenotypes.

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Seminar Dr Steven Maere on Thursday, January 24 at 11 am
by Delphine Verspeel 16 Jan '13

16 Jan '13

You are receiving this e-mail because you subscribed to our seminars announcements and reminders service at https://maillist.psb.ugent.be/mailman/listinfo/seminars . If you do not wish to receive this information anymore, please unsubscribe from future mailings at https://maillist.psb.ugent.be/mailman/options/seminars . cid:946540515@15122008-0D1CPSBcid:946540515@15122008-0D23 VIB - Department of Plant Systems Biology Technologiepark 927 B - 9052 Gent/Zwijnaarde Phone: +32 9 33 13 800 Fax: +32 9 33 13 809 Http://www.psb.vib-ugent.be

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PSB event reminder
by contact＠psb.vib-ugent.be 15 Jan '13

15 Jan '13

Calendar Name: seminars Scheduled for: Tuesday, January 15 2013, 11:00 - 12:30 Event text: Prof Lieven De Veylder VIB, Dept. of Plant Systems Biology Ghent University Gent BELGIUM Details: �DNA replication and endocycle control in arabidopsis thaliana� ABSTRACT Due to their sedentary life style, plants are unavoidably in close contact with agents that target their genome integrity. DNA stress is a recurrent problem in agriculture; not only because of an increase in UV-B irradiation due to depletion of the ozone layer, but also because of metalloid soil elements such as aluminum and boron. To sense and react to these treats, plants have evolved DNA stress checkpoint mechanisms to arrest the cell cycle when DNA replication errors or DNA breaks occur. In this way, cells can repair the damaged DNA before entering mitosis and prevent the propagation of mutations. The identification of such checkpoint mechanisms can help in obtaining corps with increased growth performance under genotoxic growth conditions. Previously we identified the cyclin-depenent kinase (CDK) inhibitory kinase WEE1 as an essential checkpoint regulator upon DNA replication stress. However, WEE1 knockout plants do not suffer from double-strand breaks, suggesting redundant checkpoint mechanisms. On basis of a compendium of microarray experiments we identified a novel group of genes that are rapidly and strongly induced upon diverse forms of DNA stress in an ATM/ATR dependent manner. The encoded proteins bind directly to CDKs, to inhibit their activity and to arrest cells in the G2 phase of the cell cycle. Through knockout analysis we illustrated that these novel proteins, in combination with WEE1, control the adaptation of plants towards DNA stress.

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PSB event reminder
by contact＠psb.vib-ugent.be 13 Jan '13

13 Jan '13

Calendar Name: seminars Scheduled for: Tuesday, January 15 2013, 11:00 - 12:30 Event text: Prof Lieven De Veylder VIB, Dept. of Plant Systems Biology Ghent University Gent BELGIUM Details: �DNA replication and endocycle control in arabidopsis thaliana� ABSTRACT Due to their sedentary life style, plants are unavoidably in close contact with agents that target their genome integrity. DNA stress is a recurrent problem in agriculture; not only because of an increase in UV-B irradiation due to depletion of the ozone layer, but also because of metalloid soil elements such as aluminum and boron. To sense and react to these treats, plants have evolved DNA stress checkpoint mechanisms to arrest the cell cycle when DNA replication errors or DNA breaks occur. In this way, cells can repair the damaged DNA before entering mitosis and prevent the propagation of mutations. The identification of such checkpoint mechanisms can help in obtaining corps with increased growth performance under genotoxic growth conditions. Previously we identified the cyclin-depenent kinase (CDK) inhibitory kinase WEE1 as an essential checkpoint regulator upon DNA replication stress. However, WEE1 knockout plants do not suffer from double-strand breaks, suggesting redundant checkpoint mechanisms. On basis of a compendium of microarray experiments we identified a novel group of genes that are rapidly and strongly induced upon diverse forms of DNA stress in an ATM/ATR dependent manner. The encoded proteins bind directly to CDKs, to inhibit their activity and to arrest cells in the G2 phase of the cell cycle. Through knockout analysis we illustrated that these novel proteins, in combination with WEE1, control the adaptation of plants towards DNA stress.

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PSB event reminder
by contact＠psb.vib-ugent.be 10 Jan '13

10 Jan '13

Calendar Name: seminars Scheduled for: Thursday, January 10 2013, 11:00 - 12:30 Event text: Prof Shaul Yalovsky Department of Molecular Biology and Ecology of Plants Tel Aviv University Tel Aviv ISRAEL Details: �ROP and Ca2+ signalling regulated patterning in Arabidopsis� ABSTRACT The ability of plants to continuously regenerate their organs is a fascinating phenomenon that depends on the competence of cells to acquire a meristematic state. In the root, regeneration depends on asymmetric auxin distribution, which is facilitated by PIN-dependent polar transport. Hence, it is conceivable that cellular mechanisms that regulate PIN polarity should affect root regeneration. Our studies provide links between ROP GTPase-regulated cell polarity, auxin distribution, root regeneration and Ca2+ signaling. In my talk I will present published an unpublished data from our work on ROPs and the ROP effector ICR1 and discuss their implications.

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Seminar Prof Lieven De Veylder on Tuesday, January 15 at 11 am
by Delphine Verspeel 09 Jan '13

09 Jan '13

You are receiving this e-mail because you subscribed to our seminars announcements and reminders service at https://maillist.psb.ugent.be/mailman/listinfo/seminars . If you do not wish to receive this information anymore, please unsubscribe from future mailings at https://maillist.psb.ugent.be/mailman/options/seminars . cid:946540515@15122008-0D1CPSBcid:946540515@15122008-0D23 VIB - Department of Plant Systems Biology Technologiepark 927 B - 9052 Gent/Zwijnaarde Phone: +32 9 33 13 800 Fax: +32 9 33 13 809 Http://www.psb.vib-ugent.be

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PSB event reminder
by contact＠psb.vib-ugent.be 08 Jan '13

08 Jan '13

Calendar Name: seminars Scheduled for: Thursday, January 10 2013, 11:00 - 12:30 Event text: Prof Shaul Yalovsky Department of Molecular Biology and Ecology of Plants Tel Aviv University Tel Aviv ISRAEL Details: �ROP and Ca2+ signalling regulated patterning in Arabidopsis� ABSTRACT The ability of plants to continuously regenerate their organs is a fascinating phenomenon that depends on the competence of cells to acquire a meristematic state. In the root, regeneration depends on asymmetric auxin distribution, which is facilitated by PIN-dependent polar transport. Hence, it is conceivable that cellular mechanisms that regulate PIN polarity should affect root regeneration. Our studies provide links between ROP GTPase-regulated cell polarity, auxin distribution, root regeneration and Ca2+ signaling. In my talk I will present published an unpublished data from our work on ROPs and the ROP effector ICR1 and discuss their implications.

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Seminar Prof Yalovsky on THURSDAY, JANUARY 10 at 11 AM (Abstract to be announced)
by Delphine Verspeel 08 Jan '13

08 Jan '13

You are receiving this e-mail because you subscribed to our seminars announcements and reminders service at https://maillist.psb.ugent.be/mailman/listinfo/seminars . If you do not wish to receive this information anymore, please unsubscribe from future mailings at https://maillist.psb.ugent.be/mailman/options/seminars . cid:946540515@15122008-0D1CPSBcid:946540515@15122008-0D23 VIB - Department of Plant Systems Biology Technologiepark 927 B - 9052 Gent/Zwijnaarde Phone: +32 9 33 13 800 Fax: +32 9 33 13 809 Http://www.psb.vib-ugent.be

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PSB event reminder
by contact＠psb.vib-ugent.be 08 Jan '13

08 Jan '13

Calendar Name: seminars Scheduled for: Thursday, January 10 2013, 11:00 - 12:30 Event text: Prof Shaul Yalovsky Department of Molecular Biology and Ecology of Plants Tel Aviv University Tel Aviv ISRAEL Details: �ROP and Ca2+ signalling regulated patterning in Arabidopsis�

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