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Circadian rhythms in insect disease vectors.

Meireles-Filho AC, Kyriacou CP - Mem. Inst. Oswaldo Cruz (2013)

Bottom Line: We have recently witnessed a substantial advance in molecular studies of circadian clocks in insect vector species that has consolidated behavioural data collected over many years, which provided insights into the regulation of the clock in the wild.Next generation sequencing technologies will facilitate the study of vector genomes/transcriptomes both among and within species and illuminate some of the species-specific patterns of adaptive circadian phenotypes that are observed in the field and in the laboratory.In this review we will explore these recent findings and attempt to identify potential areas for further investigation.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Systems Biology and Genetics, Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Switzerland, Lausanne, Laboratory of Systems Biology and Genetics, Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.

ABSTRACT
Organisms from bacteria to humans have evolved under predictable daily environmental cycles owing to the Earth's rotation. This strong selection pressure has generated endogenous circadian clocks that regulate many aspects of behaviour, physiology and metabolism, anticipating and synchronising internal time-keeping to changes in the cyclical environment. In haematophagous insect vectors the circadian clock coordinates feeding activity, which is important for the dynamics of pathogen transmission. We have recently witnessed a substantial advance in molecular studies of circadian clocks in insect vector species that has consolidated behavioural data collected over many years, which provided insights into the regulation of the clock in the wild. Next generation sequencing technologies will facilitate the study of vector genomes/transcriptomes both among and within species and illuminate some of the species-specific patterns of adaptive circadian phenotypes that are observed in the field and in the laboratory. In this review we will explore these recent findings and attempt to identify potential areas for further investigation.

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: model of the Drosophila melanogaster molecular clock comprising the twotranscriptional/translational feedback loops mechanism and the light inputpathway. CLK: Clock; CYK: Cycle; PDP1: PAR-domain protein 1; PER: Period; TIM:Timeless; Ubq: ubiquitin; VRI: Vrille.
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f01: : model of the Drosophila melanogaster molecular clock comprising the twotranscriptional/translational feedback loops mechanism and the light inputpathway. CLK: Clock; CYK: Cycle; PDP1: PAR-domain protein 1; PER: Period; TIM:Timeless; Ubq: ubiquitin; VRI: Vrille.

Mentions: The intracellular circadian pacemaker - Endogenous circadian rhythmicityis generated at the molecular level by interlocked transcriptional and translationalfeedback loops, which are autonomously operational in many cell types ( Fig. 1 ). In the two main loops, the transcriptionfactors coded by Clock ( Clk ) and cycle( cyc ) heterodimerise and bind to E-box ( CACGTG )upstream regulatory regions of the genes per , timeless (tim ), vrille ( vri ) andPAR-domain protein 1 ( Pdp1 ), activating theirexpression ( Fig. 2 ) ( Hao et al. 1997 , Allada et al.1998 , Darlington et al. 1998 , Rutila et al. 1998 , Cyran et al. 2003 , Glossop et al. 2003). In the first loop, PER and TIM proteins start to accumulate in the cytoplasm at ZT12[zeitgeber time where ZT0 is lights on and ZT12 is lights off in a light/dark (LD)12:12cycle], about 6-8 h after their respective mRNAs. As PER alone is unstable, itsaccumulation is dependent of its heterodimerisation with TIM ( Curtin et al. 1995 , Gekakis et al.1995 , Zeng et al. 1996 ). Upon PERstabilisation by TIM, the PER/TIM heretodimer shuttles into the nucleus and indirectlyshuts down tim and per expression by sequesteringCLK/CYC from about ZT18-ZT4 ( Lee et al. 1998 ,1999, Bae et al. 2000 , Yu et al. 2006 ). Without CLK/CYC mediated activation,per and tim levels start to decrease concomitantlywith PER and TIM degradation, which consequently releases CLK/CYC inhibition, allowing anew round of transcription to occur. In a second loop, Clk transcriptionis regulated by VRI and PDP1, which compete for the same VRI/PDP1-boxes in theClk promoter. While VRI represses Clk transcription ataround ZT14, PDP1 activates it around ZT18, which creates cyclical production ofClk ( Cyran et al. 2003 , Glossop et al. 2003 ) ( Fig. 1 ). The pacemaker is also regulated at the posttranslational level by thekinases doubletime, shaggy, casein kinase 2 and the phosphatase PP2A ,which have important roles in controlling the stability and nuclear entry of clock proteins( Price et al. 1998 , Martinek et al. 2001 , Lin et al.2002 , Sathyanarayanan et al. 2004 ).These transcriptional/translational regulatory loops generate circadian gene expression ofits component molecules in different phases, except for cyc , which isconstitutively expressed ( Fig. 2 ). The periodicproduction of TFs is of vital importance for the clock output, as we discuss below.


Circadian rhythms in insect disease vectors.

Meireles-Filho AC, Kyriacou CP - Mem. Inst. Oswaldo Cruz (2013)

: model of the Drosophila melanogaster molecular clock comprising the twotranscriptional/translational feedback loops mechanism and the light inputpathway. CLK: Clock; CYK: Cycle; PDP1: PAR-domain protein 1; PER: Period; TIM:Timeless; Ubq: ubiquitin; VRI: Vrille.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4109179&req=5

f01: : model of the Drosophila melanogaster molecular clock comprising the twotranscriptional/translational feedback loops mechanism and the light inputpathway. CLK: Clock; CYK: Cycle; PDP1: PAR-domain protein 1; PER: Period; TIM:Timeless; Ubq: ubiquitin; VRI: Vrille.
Mentions: The intracellular circadian pacemaker - Endogenous circadian rhythmicityis generated at the molecular level by interlocked transcriptional and translationalfeedback loops, which are autonomously operational in many cell types ( Fig. 1 ). In the two main loops, the transcriptionfactors coded by Clock ( Clk ) and cycle( cyc ) heterodimerise and bind to E-box ( CACGTG )upstream regulatory regions of the genes per , timeless (tim ), vrille ( vri ) andPAR-domain protein 1 ( Pdp1 ), activating theirexpression ( Fig. 2 ) ( Hao et al. 1997 , Allada et al.1998 , Darlington et al. 1998 , Rutila et al. 1998 , Cyran et al. 2003 , Glossop et al. 2003). In the first loop, PER and TIM proteins start to accumulate in the cytoplasm at ZT12[zeitgeber time where ZT0 is lights on and ZT12 is lights off in a light/dark (LD)12:12cycle], about 6-8 h after their respective mRNAs. As PER alone is unstable, itsaccumulation is dependent of its heterodimerisation with TIM ( Curtin et al. 1995 , Gekakis et al.1995 , Zeng et al. 1996 ). Upon PERstabilisation by TIM, the PER/TIM heretodimer shuttles into the nucleus and indirectlyshuts down tim and per expression by sequesteringCLK/CYC from about ZT18-ZT4 ( Lee et al. 1998 ,1999, Bae et al. 2000 , Yu et al. 2006 ). Without CLK/CYC mediated activation,per and tim levels start to decrease concomitantlywith PER and TIM degradation, which consequently releases CLK/CYC inhibition, allowing anew round of transcription to occur. In a second loop, Clk transcriptionis regulated by VRI and PDP1, which compete for the same VRI/PDP1-boxes in theClk promoter. While VRI represses Clk transcription ataround ZT14, PDP1 activates it around ZT18, which creates cyclical production ofClk ( Cyran et al. 2003 , Glossop et al. 2003 ) ( Fig. 1 ). The pacemaker is also regulated at the posttranslational level by thekinases doubletime, shaggy, casein kinase 2 and the phosphatase PP2A ,which have important roles in controlling the stability and nuclear entry of clock proteins( Price et al. 1998 , Martinek et al. 2001 , Lin et al.2002 , Sathyanarayanan et al. 2004 ).These transcriptional/translational regulatory loops generate circadian gene expression ofits component molecules in different phases, except for cyc , which isconstitutively expressed ( Fig. 2 ). The periodicproduction of TFs is of vital importance for the clock output, as we discuss below.

Bottom Line: We have recently witnessed a substantial advance in molecular studies of circadian clocks in insect vector species that has consolidated behavioural data collected over many years, which provided insights into the regulation of the clock in the wild.Next generation sequencing technologies will facilitate the study of vector genomes/transcriptomes both among and within species and illuminate some of the species-specific patterns of adaptive circadian phenotypes that are observed in the field and in the laboratory.In this review we will explore these recent findings and attempt to identify potential areas for further investigation.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Systems Biology and Genetics, Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Switzerland, Lausanne, Laboratory of Systems Biology and Genetics, Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.

ABSTRACT
Organisms from bacteria to humans have evolved under predictable daily environmental cycles owing to the Earth's rotation. This strong selection pressure has generated endogenous circadian clocks that regulate many aspects of behaviour, physiology and metabolism, anticipating and synchronising internal time-keeping to changes in the cyclical environment. In haematophagous insect vectors the circadian clock coordinates feeding activity, which is important for the dynamics of pathogen transmission. We have recently witnessed a substantial advance in molecular studies of circadian clocks in insect vector species that has consolidated behavioural data collected over many years, which provided insights into the regulation of the clock in the wild. Next generation sequencing technologies will facilitate the study of vector genomes/transcriptomes both among and within species and illuminate some of the species-specific patterns of adaptive circadian phenotypes that are observed in the field and in the laboratory. In this review we will explore these recent findings and attempt to identify potential areas for further investigation.

Show MeSH
Related in: MedlinePlus