Review
Copyright ©2012 Baishideng Publishing Group Co.
World J Biol Chem. Jan 26, 2012; 3(1): 7-26
Published online Jan 26, 2012. doi: 10.4331/wjbc.v3.i1.7
Figure 8
Figure 8 Schematic representation of the three well-characterized functions of the TRAMP4/5 complex. A: Processing and degradation of NAB2 mRNA: the level of NAB2 mRNA is controlled by Nab2p, which recruits TRAMP and the exosome by binding to the A26 site of the mRNA. Once TRAMP and the exosome are recruited the transcript is degraded; B: Degradation of un-modified/misfolded tRNA: tRNA that has not undergone modification at the correct time is preferentially polyadenylated by TRAMP. Once polyadenylated, the exosome aided by Mtr4p degrades the tRNA; C: ncRNA degradation: shown in panel C is the degradation of CUTs. The same pathway is followed for snRNA and snoRNA, which are processed and degraded by TRAMP and the exosome. Degradation of CUTs is performed co-transcriptionally as pictured. The levels of these RNAs cannot be detected without depletion of Rrp6p or Trf4p[92,111,112].