skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Co-expression networks in Chlamydomonas reveal significant rhythmicity in batch cultures and empower gene function discovery

Journal Article · · The Plant Cell
 [1]; ORCiD logo [2]
  1. Univ. of California, Los Angeles, CA (United States)
  2. Univ. of California, Los Angeles, CA (United States); Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

The unicellular green alga Chlamydomonas reinhardtii is a choice reference system for the study of photosynthesis and chloroplast metabolism, cilium assembly and function, lipid and starch metabolism, and metal homeostasis. Despite decades of research, the functions of thousands of genes remain largely unknown, and new approaches are needed to categorically assign genes to cellular pathways. Growing collections of transcriptome and proteome data now allow a systematic approach based on integrative co-expression analysis. We used a dataset comprising 518 deep transcriptome samples derived from 58 independent experiments to identify potential co-expression relationships between genes. We visualized co-expression potential with the R package corrplot, to easily assess co-expression and anti-correlation between genes. We extracted several hundred high-confidence genes at the intersection of multiple curated lists involved in cilia, cell division, and photosynthesis, illustrating the power of our method. Surprisingly, Chlamydomonas experiments retained a significant rhythmic component across the transcriptome, suggesting an underappreciated variable during sample collection, even in samples collected in constant light. Our results therefore document substantial residual synchronization in batch cultures, contrary to assumptions of asynchrony. We provide step-by-step protocols for the analysis of co-expression across transcriptome data sets from Chlamydomonas and other species to help foster gene function discovery.

Research Organization:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Biological and Environmental Research (BER)
Grant/Contract Number:
AC02-05CH11231; FC02-02ER63421; SC0018301
OSTI ID:
1814429
Journal Information:
The Plant Cell, Vol. 33, Issue 4; ISSN 1040-4651
Publisher:
American Society of Plant BiologistsCopyright Statement
Country of Publication:
United States
Language:
English

References (88)

ManiNetCluster: a novel manifold learning approach to reveal the functional links between gene networks journal December 2019
Flagellar Elongation and Shortening in Chlamydomonas journal May 1969
Single-cell RNA sequencing of batch Chlamydomonas cultures reveals heterogeneity in their diurnal cycle phase journal February 2021
Ccm1, a regulatory gene controlling the induction of a carbon-concentrating mechanism in Chlamydomonas reinhardtii by sensing CO2 availability journal April 2001
We aren’t good at picking candidate genes, and it’s slowing us down journal April 2020
Rescue of a paralyzed-flagella mutant of Chlamydomonas by transformation. journal August 1990
STAR: ultrafast universal RNA-seq aligner journal October 2012
Impact of Oxidative Stress on Ascorbate Biosynthesis in Chlamydomonas via Regulation of the VTC2 Gene Encoding a GDP-l-galactose Phosphorylase journal March 2012
Lack of the D2 protein in a Chlamydomonas reinhardtii psb D mutant affects photosystem II stability and D1 expression journal August 1986
A Global Coexpression Network Approach for Connecting Genes to Specialized Metabolic Pathways in Plants journal April 2017
Circadian Phase Has Profound Effects on Differential Expression Analysis journal November 2012
Correlation between transcriptome and interactome mapping data from Saccharomyces cerevisiae journal November 2001
IFT Proteins Accumulate during Cell Division and Localize to the Cleavage Furrow in Chlamydomonas journal February 2012
A genome-wide algal mutant library and functional screen identifies genes required for eukaryotic photosynthesis journal March 2019
Mutant phenotypes support a trans-splicing mechanism for the expression of the tripartite psaA gene in the C. reinhardtii chloroplast journal March 1988
High-frequency nuclear transformation of Chlamydomonas reinhardtii. journal February 1990
Regulation of photoprotection gene expression in Chlamydomonas by a putative E3 ubiquitin ligase complex and a homolog of CONSTANS journal August 2019
The Cia5 gene controls formation of the carbon concentrating mechanism in Chlamydomonas reinhardtii journal April 2001
Studies on mutants deficient in the photosystem I reaction centers in Chlamydomonas reinhardtii journal December 1980
Proteomic analysis of a eukaryotic cilium journal July 2005
Comparative Genomics Identifies a Flagellar and Basal Body Proteome that Includes the BBS5 Human Disease Gene journal May 2004
Mutants of Chlamydomonas moewusii with Impaired Motility journal December 1954
Arabidopsis CSP41 proteins form multimeric complexes that bind and stabilize distinct plastid transcripts journal November 2011
Transcriptional Regulation of Ribosome Components Are Determined by Stress According to Cellular Compartments in Arabidopsis thaliana journal December 2011
Zinc Deficiency Impacts CO 2 Assimilation and Disrupts Copper Homeostasis in Chlamydomonas reinhardtii journal February 2013
Co-expression tools for plant biology: opportunities for hypothesis generation and caveats journal December 2009
Fe Sparing and Fe Recycling Contribute to Increased Superoxide Dismutase Capacity in Iron-Starved Chlamydomonas reinhardtii journal June 2012
Isolation and Characterization of Photoautotrophic Mutants ofChlamydomonas reinhardtii Deficient in State Transition journal October 1999
Subcellular metal imaging identifies dynamic sites of Cu accumulation in Chlamydomonas journal October 2014
ALCOdb: Gene Coexpression Database for Microalgae journal December 2015
Changes in Transcript Abundance in Chlamydomonas reinhardtii following Nitrogen Deprivation Predict Diversion of Metabolism journal October 2010
The Genetics of Photosynthesis and of the Chloroplast in Chlamydomonas Reinhardi journal December 1970
Nitrogen-Sparing Mechanisms in Chlamydomonas Affect the Transcriptome, the Proteome, and Photosynthetic Metabolism journal April 2014
Transcriptome-Wide Changes in Chlamydomonas reinhardtii Gene Expression Regulated by Carbon Dioxide and the CO 2 -Concentrating Mechanism Regulator CIA5 / CCM1 journal May 2012
Chlamydomonas reinhardtii Secretes Compounds That Mimic Bacterial Signals and Interfere with Quorum Sensing Regulation in Bacteria journal January 2004
Between a rock and a hard place: Trace element nutrition in Chlamydomonas journal July 2006
Lineage-specific chromatin signatures reveal a regulator of lipid metabolism in microalgae journal July 2015
Gene isolation through genomic complementation using an indexed library of Chlamydomonas reinhardtii DNA journal February 1994
A Screening Technique for Photosynthetic Mutants in Unicellular Algæ journal October 1960
Reciprocal Interaction of the Circadian Clock with the Iron Homeostasis Network in Arabidopsis     journal December 2012
ChlamyNET: a Chlamydomonas gene co-expression network reveals global properties of the transcriptome and the early setup of key co-expression patterns in the green lineage journal March 2016
Proteomic Analysis of Isolated Chlamydomonas Centrioles Reveals Orthologs of Ciliary-Disease Genes journal June 2005
Systems-Level Analysis of Nitrogen Starvation-Induced Modifications of Carbon Metabolism in a Chlamydomonas reinhardtii Starchless Mutant journal November 2013
The Chlamydomonas Genome Reveals the Evolution of Key Animal and Plant Functions journal October 2007
Rank of Correlation Coefficient as a Comparable Measure for Biological Significance of Gene Coexpression journal September 2009
Genome-wide analysis on Chlamydomonas reinhardtii reveals the impact of hydrogen peroxide on protein stress responses and overlap with other stress transcriptomes journal December 2015
Cell-Type Transcriptomes of the Multicellular Green Alga Volvox carteri Yield Insights into the Evolutionary Origins of Germ and Somatic Differentiation Programs journal February 2018
Identification of a chloroplast ribosomal protein altered by a chloroplast mutation in Chlamydomonas. journal May 1975
Role of Chloroplast Protein Kinase Stt7 in LHCII Phosphorylation and State Transition in Chlamydomonas journal March 2003
Iron Is Involved in the Maintenance of Circadian Period Length in Arabidopsis       journal January 2013
The Chlamydomonas cell cycle journal March 2015
RNA-Seq Analysis of Sulfur-Deprived Chlamydomonas Cells Reveals Aspects of Acclimation Critical for Cell Survival journal June 2010
Circadian clock adjustment to plant iron status depends on chloroplast and phytochrome function journal December 2012
Phosphoprotein SAK1 is a regulator of acclimation to singlet oxygen in Chlamydomonas reinhardtii journal May 2014
Integrating large-scale functional genomic data to dissect the complexity of yeast regulatory networks journal June 2008
Bilin-Dependent Photoacclimation in Chlamydomonas reinhardtii journal October 2017
The dynamics and regulators of cell fate decisions are revealed by pseudotemporal ordering of single cells journal March 2014
BioVenn – a web application for the comparison and visualization of biological lists using area-proportional Venn diagrams journal January 2008
Algal Dual-Specificity Tyrosine Phosphorylation-Regulated Kinase, Triacylglycerol Accumulation Regulator1, Regulates Accumulation of Triacylglycerol in Nitrogen or Sulfur Deficiency journal April 2015
Beyond Complementation. Map-Based Cloning in Chlamydomonas reinhardtii journal January 2005
PF16 encodes a protein with armadillo repeats and localizes to a single microtubule of the central apparatus in Chlamydomonas flagella journal February 1996
Ni induces the CRR1-dependent regulon revealing overlap and distinction between hypoxia and Cu deficiency responses in Chlamydomonas reinhardtii journal January 2016
Comprehensive Discovery of Cell-Cycle-Essential Pathways in Chlamydomonas reinhardtii journal May 2018
Detecting overlapping protein complexes in protein-protein interaction networks journal March 2012
Molecular-timetable methods for detection of body time and rhythm disorders from single-time-point genome-wide expression profiles journal July 2004
Large-scale insertional mutagenesis of Chlamydomonas supports phylogenomic functional prediction of photosynthetic genes and analysis of classical acetate-requiring mutants journal April 2015
Linkage maps in Chlamydomonas Reinhardi journal May 1962
Systems and Trans -System Level Analysis Identifies Conserved Iron Deficiency Responses in the Plant Lineage journal October 2012
Activation of the Carbon Concentrating Mechanism by CO 2 Deprivation Coincides with Massive Transcriptional Restructuring in Chlamydomonas reinhardtii journal May 2012
Whole-Genome Sequencing to Identify Mutants and Polymorphisms in Chlamydomonas reinhardtii journal January 2012
PSRP1 Is Not a Ribosomal Protein, but a Ribosome-binding Factor That Is Recycled by the Ribosome-recycling Factor (RRF) and Elongation Factor G (EF-G) journal February 2010
Social interactions in bacterial cell–cell signaling journal September 2016
Systems Biology Approach in Chlamydomonas Reveals Connections between Copper Nutrition and Multiple Metabolic Steps journal April 2011
Phytohormones in microalgae: a new opportunity for microalgal biotechnology? journal May 2015
Conservation and degradation of cytoplasmic and chloroplast ribosomes in Chlamydomonas reinhardtii journal May 1971
An Indexed, Mapped Mutant Library Enables Reverse Genetics Studies of Biological Processes in Chlamydomonas reinhardtii journal January 2016
Revealing static and dynamic modular architecture of the eukaryotic protein interaction network journal January 2007
Cytoplasmic and Chloroplast Ribosomes of Chlamydomonas: Ultracentrifugal Characterization journal August 1967
Molecular Map of the Chlamydomonas reinhardtii Nuclear Genome journal April 2003
Turnover of chloroplast and cytoplasmic ribosomes during gametogenesis in Chlamydomonas reinhardi journal July 1976
Prevalence, Evolution, and cis -Regulation of Diel Transcription in Chlamydomonas reinhardtii journal October 2014
Manganese co-localizes with calcium and phosphorus in Chlamydomonas acidocalcisomes and is mobilized in manganese-deficient conditions journal September 2019
A Microbial Avenue to Cell Cycle Control in the Plant Superkingdom journal October 2014
Multiomics resolution of molecular events during a day in the life of Chlamydomonas journal January 2019
eulerAPE: Drawing Area-Proportional 3-Venn Diagrams Using Ellipses journal July 2014
Complementation of a Chlamydomonas reinhardtii mutant using a genomic cosmid library journal February 1994
Regulation of Oxygenic Photosynthesis during Trophic Transitions in the Green Alga Chromochloris zofingiensis journal February 2019
Co-expression networks in Chlamydomonas reveal significant rhythmicity in batch cultures and empower gene function discovery dataset January 2021

Cited By (1)