# Mutations in Components of the TREX‐2 Complex Result in Misexpression of the Kelch‐Domain F‐Box Protein KFB39 Promoter in Arabidopsis thaliana

## TL;DR

This study finds that mutations in the TREX-2 complex lead to abnormal expression of the KFB39 gene in Arabidopsis, even without its usual trigger.

## Contribution

The novel finding is that TREX-2 complex mutations cause misexpression of the KFB39 promoter, linking nuclear pore components to gene regulation.

## Key findings

- Two mutants in TREX-2 components (SAC3B, THP1) caused misexpression of the KFB39 promoter-GUS fusion.
- Genetic analysis of sac3 mutants showed impaired growth and reduced nuclear export capacity.
- Expression patterns of SAC3 and THP1 genes were distinct from KFB39.

## Abstract

Arabidopsis thaliana
gene At2g44130 encodes a Kelch‐like domain F‐box protein designated KFB39 and was previously shown to be specifically expressed on exposure to the oxylipin cis‐jasmone. In order to better understand the regulation of At2g44130, a forward genetic screen was carried out to identify mutants in which a promoter‐GUS fusion was expressed in the absence of the inducer, cis‐jasmone. Two mutants were recovered, showing misexpression of the promoter‐GUS fusion, and surprisingly, both were found to be in components (SAC3B, THP1) of the TREX‐2 nuclear pore complex. Genetic analysis of sac3 mutants in Arabidopsis revealed additive impairments to growth and development as well as reduced capacity for nuclear export. Promoter‐GUS fusions of the Arabidopsis SAC3 and THP1 genes revealed a discrete expression pattern that was non‐overlapping with KFB39. A link between the expression of KFB39 and the TREX‐2 complex is not obvious, but we note that previously, unrelated forward genetic screens using promoter–reporter fusions have also recovered sac3b and thp1 mutants. We consider some possible explanations for these shared occurrences.