Cryptic unstable transcripts (CUTs) are rapidly degraded by the nuclear exosome. However, the mechanism by which they are recognized and targeted to the exosome is not fully understood. Here we report that the MTREC complex, which has recently been shown to promote degradation of meiotic mRNAs and regulatory ncRNAs, is also the major nuclear exosome targeting complex for CUTs and unspliced pre-...

The molecular mechanism of mRNA degradation in the chloroplast consists of sequential events, including endonucleolytic cleavage, the addition of poly(A)-rich sequences to the endonucleolytic cleavage products, and exonucleolytic degradation. In spinach chloroplasts, the latter two steps of polyadenylation and exonucleolytic degradation are performed by the same phosphorolytic and processive en...

The torpedo model of transcription termination by RNA polymerase II proposes that a 5'-3' RNA exonuclease enters at the poly(A) cleavage site, degrades the nascent RNA, and eventually displaces polymerase from the DNA. Cotranscriptional degradation of nascent RNA has not been directly demonstrated, however. Here we report that two exonucleases, Rat1 and Xrn1, both contribute to cotranscriptiona...

Double-stranded RNA, processed to small interfering RNAs (siRNAs) by Dicer and incorporated into the RNA-induced silencing complex (RISC), triggers gene silencing by a variety of pathways in eukaryotes. RNA interference involving the degradation of homologous transcripts is the best-characterized mechanism. However, the fate of the RNA fragments resulting from siRNA-directed cleavage is poorly ...

The reduced yields of rhinovirus type 2 at temperatures above 37 degrees C were shown to result from the degradation of virus-induced RNA, leaving little RNA available for inclusion into mature infectious virions. The degradation occurred about 6 h p.i., and appeared to be selectively effecting the single-stranded species. Lysosomal nucleases do not appear to have a role in this supra-optimal d...

background: rna interference (rnai) is a phenomenon uses double-stranded rna (dsrna) to specifically inhibit gene expression. the non-specific silencing caused by interferon response to dsrna in mammalian cells limits the potential of utilizing rnai to study gene function. duplexes of 21-nucleotide short interfering dsrna (sirna) inhibit gene expression by rnai. in some organisms, sirna can als...

Multiprotein complexes that carry out RNA degradation and processing functions are found in cells from all domains of life. In Escherichia coli, the RNA degradosome, a four-protein complex, is required for normal RNA degradation and processing. In addition to the degradosome complex, the cell contains other ribonucleases that also play important roles in RNA processing and/or degradation. Wheth...

In bacteria infected by T-even bacteriophages, the net synthesis of ribonucleic acid stops immediately after infection although the synthesis of protein continues actively (1, 2). However, with the use of an isotope-labeling technique, Volkin and Astrachan (3) demonstrated that a minor fraction of the total ribonucleic acid is produced soon after phage infection and that the apparent nucleotide...