Gene capture by transposable elements leads to epigenetic conflict in maize

Area of Science:

• Genomics
• Epigenetics
• Molecular Biology

Background:

• Transposable elements (TEs) can capture host gene fragments.
• Host silencing of TEs can lead to unintended silencing of captured gene regions via small interfering RNAs (siRNAs).
• This epigenetic crosstalk creates an intragenomic conflict between TE silencing and gene function.

Purpose of the Study:

• To investigate the epigenetic conflict arising from TE-mediated gene fragment capture in the maize genome.
• To analyze the impact of TE capture on donor gene function and epigenetic regulation.
• To differentiate outcomes based on gene synteny and evolutionary constraint.

Main Methods:

• Identification of TEs containing exon fragments from donor genes in the maize genome.
• Analysis of siRNA mapping, DNA methylation (CHH methylation), and gene expression.
• Comparison of patterns between syntenic and translocated donor genes.
• Categorization of genes based on evolutionary constraint.

Main Results:

• 1263 TEs captured fragments from 1629 genes; donor genes showed increased siRNAs and methylation.
• Syntenic genes maintained expression, suggesting moderated silencing for important genes.
• Translocated genes exhibited silencing signatures (high methylation, low expression).
• TEs with captured fragments were older and showed less siRNA mapping and methylation.

Conclusions:

• TE capture triggers an intragenomic epigenetic conflict.
• Functionally important genes may maintain function through moderated silencing.
• Less-constrained genes may undergo pseudogenization.
• TE capture may be linked to gene translocation events.