TCO, a Putative Transcriptional Regulator in Arabidopsis, Is a Target of the Protein Kinase CK2

Int J Mol Sci. 2018 Dec 28;20(1):99. doi: 10.3390/ijms20010099.


As multicellular organisms grow, spatial and temporal patterns of gene expression are strictly regulated to ensure that developmental programs are invoked at appropriate stages. In this work, we describe a putative transcriptional regulator in Arabidopsis, TACO LEAF (TCO), whose overexpression results in the ectopic activation of reproductive genes during vegetative growth. Isolated as an activation-tagged allele, tco-1D displays gene misexpression and phenotypic abnormalities, such as curled leaves and early flowering, characteristic of chromatin regulatory mutants. A role for TCO in this mode of transcriptional regulation is further supported by the subnuclear accumulation patterns of TCO protein and genetic interactions between tco-1D and chromatin modifier mutants. The endogenous expression pattern of TCO and gene misregulation in tco loss-of-function mutants indicate that this factor is involved in seed development. We also demonstrate that specific serine residues of TCO protein are targeted by the ubiquitous kinase CK2. Collectively, these results identify TCO as a novel regulator of gene expression whose activity is likely influenced by phosphorylation, as is the case with many chromatin regulators.

Keywords: Arabidopsis thaliana; CK2; chromatin regulation; development; phosphorylation; protein kinase; transcriptional regulation.

MeSH terms

  • Amino Acid Sequence
  • Arabidopsis / genetics*
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / chemistry
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Casein Kinase II / metabolism*
  • Chromatin / genetics
  • Chromatin / metabolism
  • Ectopic Gene Expression
  • Fluorescent Antibody Technique
  • Gene Expression Regulation, Plant*
  • Mutation
  • Organ Specificity / genetics
  • Phenotype
  • Phosphorylation
  • Promoter Regions, Genetic
  • Protein Binding
  • Reproduction / genetics
  • Seeds / genetics
  • Seeds / metabolism
  • Transcription Factors / metabolism*


  • Arabidopsis Proteins
  • Chromatin
  • Transcription Factors
  • Casein Kinase II