(A) study of fission yeast exosome complex catalytic component Rrp6 and its effect on lifespan extension

Abstract

Rrp6 is the nucleic catalytic component of exosome complex well known for its suppression of spurious transcription. The chief interest in this protein is its role in pervasive transcription. It is known that upon deletion of Rrp6, various kinds of noncoding transcripts appeared. RNA-seq was performed to see the effects of this enzyme in terms of whole genome in the fission yeast. Due to its degradation role, we expected transcription to be increased and it was rightly so along with many other transcripts. However, unexpectedly there were also many transcripts that showed decrease compared to the wild type. As decreasing transcript cannot be explained straight forward with loss of degradation activity, there was a need to look deeper into this matter. Ontologically categorizing the decreased transcripts show that the reduction was due to not a principle but, as there were clear clusters, certain design had to be at hand. Previously there were instances where increased antisense transcripts hindering sense transcripts by termination defect. However, in our research, there were signs of termination defect, but the number of the instances was not sufficient. When ontologically categorized, decreased transcripts are clustered into certain types, such as cellular respiration and ribosomal protein genes. In calorie restriction, similar pathways are distinctly changed. Calorie restriction achieves its effect by Tor pathway. Further looking into the phenotype reveals that not only does the transcription status resemble CR, but also organismal level phenotypes in that state, namely aging.