GSE128877
Transcription and export complex (THO/TREX) coordinates transcription termination in Arabidopsis
Transcription termination of mRNAs transcribed from a given locus has a decisive role in regulating the gene function as it determines the coding potential and inclusion of regulatory sequence elements. Failure in appropriate transcription termination leads to read-through transcription, resulting in the synthesis of antisense RNAs which can have profound impact on overall gene expression. However, molecular mechanisms which regulate transcription termination and chimeric RNA formation are poorly understood.   We explored the regulatory function of transcription and export complex (THO/TREX) in transcription termination. We show that two members of THO/TREX complex, TREX COMPONENT 1 (TEX1) and HYPER RECOMBINATION1(HPR1) are critical for the correct transcription termination in Arabidopsis. We first demonstrate this by showing defective termination of the bacterial nopaline synthase (NOS) terminator on a transgene in tex1 and hpr1 mutants. Additionally, we show that RNA termination defects in tex1 and hpr1 mutants are widespread at the whole genome levels leading to 3'UTR extensions, truncations and in some cases in the formation of intergenic chimeric transcripts. Chromatin immunoprecipitation coupled with quantitative PCR experiments confirmed the presence of RNA polymerase II beyond the canonical termination sites on genes with defective RNA termination in tex1 and hpr1 mutants. These results demonstrate that THO/TREX complex is a novel regulator of transcription termination in Arabidopsis. Overall design: RNAs from Arabidopsis thaliana roots with different genotypes (WT, tex1-4, pho1-7, pho1-7tex1-4 and pho1-7hpr1-5 were extracted and sequenced, with 2 or 3 biological replicate per genotype.