Limits...
Silencing signals in plants: a long journey for small RNAs.

Molnar A, Melnyk C, Baulcombe DC - Genome Biol. (2011)

Bottom Line: Recent research shows that short RNA molecules act as mobile signals that direct mRNA cleavage and DNA methylation in recipient cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK. am798@cam.ac.uk

ABSTRACT
Recent research shows that short RNA molecules act as mobile signals that direct mRNA cleavage and DNA methylation in recipient cells.

Show MeSH
Schematic diagram of silencing pathways in plants. An overview of the (a) microRNA, (b) trans-acting siRNA, (c) viral siRNA and (d) heterochromatic siRNA pathways. sRNAs are processed from partially or perfectly double-stranded RNA (dsRNA) precursor molecules by Dicer-like (DCL) proteins. They are incorporated into Argonaute (AGO) complexes to target nucleic acids. RNA-dependent RNA polymerases (RDRs) convert transcripts generated by DNA-dependent RNA polymerase II (POL II) and IV (POL IV) into dsRNA. The associated RDR, DCL and AGO proteins that function in each pathway and the sizes and functions of the sRNAs produced are indicated. RISC refers to the RNA-induced silencing complex, a multiprotein complex that consists of an AGO protein, an sRNA and other protein factors. The different compositions of RISC complexes are indicated in different colors.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3091295&req=5

Figure 1: Schematic diagram of silencing pathways in plants. An overview of the (a) microRNA, (b) trans-acting siRNA, (c) viral siRNA and (d) heterochromatic siRNA pathways. sRNAs are processed from partially or perfectly double-stranded RNA (dsRNA) precursor molecules by Dicer-like (DCL) proteins. They are incorporated into Argonaute (AGO) complexes to target nucleic acids. RNA-dependent RNA polymerases (RDRs) convert transcripts generated by DNA-dependent RNA polymerase II (POL II) and IV (POL IV) into dsRNA. The associated RDR, DCL and AGO proteins that function in each pathway and the sizes and functions of the sRNAs produced are indicated. RISC refers to the RNA-induced silencing complex, a multiprotein complex that consists of an AGO protein, an sRNA and other protein factors. The different compositions of RISC complexes are indicated in different colors.

Mentions: The diversity of RNA silencing pathways in plants is illustrated by functions of the DCL family members. DCL1 produces 21-nt sRNAs called microRNAs (miRNAs) from a partly double-stranded region of imperfectly matched foldback RNAs [6,7] to regulate the expression of mRNAs with complementary target sites (Figure 1a). DCL2 generates 22-nt small interfering RNAs (siRNAs) from double-stranded viral RNAs and transgenes [8,9] (Figure 1c). DCL3 produces repeat-associated, transposon-specific and transgene-derived 24-nt siRNAs to induce changes in heterochromatin using precursor dsRNAs that are generated by the coordinated action of the plant-specific DNA-dependant RNA polymerase IV (POL IV) and RDR2 [10,11] (Figure 1d). Finally, DCL4 produces 21-nt trans-acting siRNAs (tasiRNAs) from the non-coding transcripts of TAS genes that have been converted after a miRNA-mediated cleavage into dsRNAs by RDR6 [12,13] (Figure 1b). These tasiRNAs act via AGO1 or AGO7 to control hormone response and leaf polarity [14]. DCL4 also produces siRNAs from viruses and transgenes [8,15] (Figure 1c).


Silencing signals in plants: a long journey for small RNAs.

Molnar A, Melnyk C, Baulcombe DC - Genome Biol. (2011)

Schematic diagram of silencing pathways in plants. An overview of the (a) microRNA, (b) trans-acting siRNA, (c) viral siRNA and (d) heterochromatic siRNA pathways. sRNAs are processed from partially or perfectly double-stranded RNA (dsRNA) precursor molecules by Dicer-like (DCL) proteins. They are incorporated into Argonaute (AGO) complexes to target nucleic acids. RNA-dependent RNA polymerases (RDRs) convert transcripts generated by DNA-dependent RNA polymerase II (POL II) and IV (POL IV) into dsRNA. The associated RDR, DCL and AGO proteins that function in each pathway and the sizes and functions of the sRNAs produced are indicated. RISC refers to the RNA-induced silencing complex, a multiprotein complex that consists of an AGO protein, an sRNA and other protein factors. The different compositions of RISC complexes are indicated in different colors.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3091295&req=5

Figure 1: Schematic diagram of silencing pathways in plants. An overview of the (a) microRNA, (b) trans-acting siRNA, (c) viral siRNA and (d) heterochromatic siRNA pathways. sRNAs are processed from partially or perfectly double-stranded RNA (dsRNA) precursor molecules by Dicer-like (DCL) proteins. They are incorporated into Argonaute (AGO) complexes to target nucleic acids. RNA-dependent RNA polymerases (RDRs) convert transcripts generated by DNA-dependent RNA polymerase II (POL II) and IV (POL IV) into dsRNA. The associated RDR, DCL and AGO proteins that function in each pathway and the sizes and functions of the sRNAs produced are indicated. RISC refers to the RNA-induced silencing complex, a multiprotein complex that consists of an AGO protein, an sRNA and other protein factors. The different compositions of RISC complexes are indicated in different colors.
Mentions: The diversity of RNA silencing pathways in plants is illustrated by functions of the DCL family members. DCL1 produces 21-nt sRNAs called microRNAs (miRNAs) from a partly double-stranded region of imperfectly matched foldback RNAs [6,7] to regulate the expression of mRNAs with complementary target sites (Figure 1a). DCL2 generates 22-nt small interfering RNAs (siRNAs) from double-stranded viral RNAs and transgenes [8,9] (Figure 1c). DCL3 produces repeat-associated, transposon-specific and transgene-derived 24-nt siRNAs to induce changes in heterochromatin using precursor dsRNAs that are generated by the coordinated action of the plant-specific DNA-dependant RNA polymerase IV (POL IV) and RDR2 [10,11] (Figure 1d). Finally, DCL4 produces 21-nt trans-acting siRNAs (tasiRNAs) from the non-coding transcripts of TAS genes that have been converted after a miRNA-mediated cleavage into dsRNAs by RDR6 [12,13] (Figure 1b). These tasiRNAs act via AGO1 or AGO7 to control hormone response and leaf polarity [14]. DCL4 also produces siRNAs from viruses and transgenes [8,15] (Figure 1c).

Bottom Line: Recent research shows that short RNA molecules act as mobile signals that direct mRNA cleavage and DNA methylation in recipient cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK. am798@cam.ac.uk

ABSTRACT
Recent research shows that short RNA molecules act as mobile signals that direct mRNA cleavage and DNA methylation in recipient cells.

Show MeSH