Posttranscriptional gene silencing in nuclei

Posttranscriptional gene silencing in nuclei.

In plants, small interfering RNAs (siRNAs) with sequence homology to transcribed regions of genes can guide the sequence-specific degradation of corresponding mRNAs, leading to posttranscriptional gene silencing (PTGS). The current consensus is that siRNA-mediated PTGS occurs primarily in the cytoplasm where target mRNAs are localized and translated into proteins. However, expression of an inve...

SnapShot: Posttranscriptional Gene Silencing

Transcriptional and posttranscriptional gene silencing are mechanistically related

Two distinct gene-silencing phenomena are observed in plants: transcriptional gene silencing (TGS), which involves decreased RNA synthesis because of promoter methylation, and posttranscriptional gene silencing (PTGS), which involves sequence-specific RNA degradation. PTGS is induced by deliberate [1-4] or fortuitous production (R.v.B., unpublished data) of double-stranded RNA (dsRNA). TGS coul...

Human RISC Couples MicroRNA Biogenesis and Posttranscriptional Gene Silencing

RNA interference is implemented through the action of the RNA-induced silencing complex (RISC). Although Argonaute2 has been identified as the catalytic center of RISC, the RISC polypeptide composition and assembly using short interfering RNA (siRNA) duplexes has remained elusive. Here we show that RISC is composed of Dicer, the double-stranded RNA binding protein TRBP, and Argonaute2. We demon...

Effects of local mRNA structure on posttranscriptional gene silencing.

Antisense oligodeoxynucleotides (AONs) and short interfering RNAs (siRNAs) effect posttranscriptional gene silencing (PTGS) by hybridizing to an mRNA and then directing its cleavage. To understand the constraints that mRNA structure imposes on AON- vs. siRNA-mediated PTGS, AON- and siRNA-mediated cleavage of defined mRNA structures was monitored in Drosophila embryo whole-cell lysates. We obser...