The Lingulodinium circadian system lacks rhythmic changes in transcript abundance

BMC Biology

Research Article

Louis Letourneau¹  Sougata Roy²  Steve Dagenais-Bellefeuille²  David Morse²  Mathieu Beauchemin²  Mario Cappadocia² 

[1] Centre d’Innovation Génome Québec, McGill University, 740 Docteur Penfield, H3A 1A4, Montréal, Québec, Canada;Département de Sciences Biologiques, Université de Montréal, Institut de Recherche en Biologie Végétale, 4101 Sherbrooke est, H1X 2B2, Montréal, Québec, Canada;

关键词: Transcript profiling;    RNA Seq;    Circadian rhythms;    Dinoflagellate;   

DOI  :  10.1186/s12915-014-0107-z

 received in 2014-08-28, accepted in 2014-12-09,  发布年份 2014

来源: Springer

【 摘 要 】

BackgroundAlmost all cells display circadian rhythms, approximately 24-hour period changes in their biochemistry, physiology or behavior. These rhythms are orchestrated by an endogenous circadian clock whose mechanism is based on transcription-translation feedback loops (TTFL) where the translated products of clock genes act to inhibit their own transcription.ResultsWe have used RNA-Seq to measure the abundance of all transcripts in an RNA-Seq-derived de novo gene catalog in two different experiments. One compared midday and midnight in a light–dark cycle (ZT6 and ZT18) and under constant light (CT6 and CT18). The second compared four different times (ZT2, ZT6, ZT14 and ZT18) under a light dark cycle. We show here that despite an elaborate repertoire of biological rhythms, the unicellular dinoflagellate Lingulodinium had no detectable daily variation in the abundance of any transcript in an RNA-Seq-derived de novo gene catalog. We also examined the timing of the bioluminescence and photosynthesis rhythms in the presence of the transcription inhibitors actinomycin D and cordycepin. We found that the timing of the two rhythms was unchanged even when transcription rates had decreased to roughly 5% the levels of untreated cells.ConclusionsThe lack of detectable daily variation in transcript levels indicates that the endogenous circadian timer of Lingulodinium does not require rhythmic RNA. If the circadian timer is considered as a limit cycle oscillator, then cellular time in this organism must be defined by variations in state variables that do not include the amount of a clock gene transcript.

【 授权许可】

Unknown   
© Roy et al.; licensee BioMed Central. 2014. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.