Condensins are genome organisers that shape chromosomes and promote their
accurate transmission. Several studies have also implicated condensins in gene expression,
although any mechanisms have remained enigmatic. Here, we report on the role of condensin in
gene expression in fission and budding yeasts. In contrast to previous studies, we provide
compelling evidence that condensin plays no direct role in the maintenance of the transcriptome,
neither during interphase nor during mitosis. We further show that the changes in gene expression
in post-mitotic fission yeast cells that result from condensin inactivation are largely a consequence
of chromosome missegregation during anaphase, which notably depletes the RNA-exosome from
daughter cells. Crucially, preventing karyotype abnormalities in daughter cells restores a normal
transcriptome despite condensin inactivation. Thus, chromosome instability, rather than a direct
role of condensin in the transcription process, changes gene expression. This knowledge challenges
the concept of gene regulation by canonical condensin complexes.