DNA methylation and histone modifications are important epigenetic markers involved in transcriptional gene regulation in animals and plants. In Arabidopsis, IDM1 is a histone acetyltransferase that plays critical roles in preventing hypermethylation of DNA and transcriptional gene silencing, but the mechanism(s) by which IDM1 is targeted to specific genomic loci is still unclear. Here, we find two new components of the IDM1 complex, IDAP1 and IDAP2, which bear high similarities to the transposase and myb‐like DNA‐binding protein of PIF/Harbinger transposons, respectively. Dysfunction of IDAP1 or IDAP2 causes DNA hypermethylation and repression of reporter genes as well as endogenous genes. IDAP1 interacts with IDAP2, and they form a protein complex with IDM1. Furthermore, IDAP2 has DNA‐binding activity, which facilitates the recruitment of IDM1 to its target loci. We propose that IDAP1 and IDAP2, co‐opted from ancient PIF/Harbinger‐like transposon proteins, act together with IDM1 to regulate active DNA demethylation in higher plants.
A pair of transposon‐derived proteins regulates active DNA demethylation and transcriptional anti‐silencing through interacting with the histone acetyltransferase IDM1 in Arabidopsis.
Transposable elements are important sources of new genes during evolution.
IDAP1 and IDAP2 encode two proteins related to the PIF/Harbinger DNA transposases.
IDAP1 and IDAP2 prevent DNA hypermethylation and transcriptional gene silencing.
IDAP1 and IDAP2 physically associate with IDM1, IDM2, IDL1, and MBD7.
IDAP1 and IDAP2 are required for the proper function of IDM1 in vivo.
- Received March 8, 2016.
- Revision received June 21, 2016.
- Accepted July 5, 2016.
- © 2016 The Authors