Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)

Editor

Personal info

View

About

Terms

Javascript disabled

Please enable Javascript support in your browser to use this application.

Instructions on how to enable JavaScript on different browsers can be found here: http://www.google.com/support/bin/answer.py?answer=23852.

[edit this page]

Gene Review:

AGO4 - argonaute 4

Arabidopsis thaliana

Synonyms: ARGONAUTE 4, OCP11, OVEREXPRESSOR OF CATIONIC PEROXIDASE 11, T20P8.9, T20P8_9

Li, C.F. et al., Zheng, X. et al., Zilberman, D. et al., Jones, L. et al., Zilberman, D. et al.

Welcome! If you are familiar with the subject of this article, you can contribute to this open access knowledge base by deleting incorrect information, restructuring or completely rewriting any text. Read more.

High impact information on AGO4

Our results suggest a function for Cajal bodies as a center for the assembly of an AGO4/NRPD1b/siRNA complex, facilitating its function in RNA-directed gene silencing at target loci [1].
ARGONAUTE4 (AGO4) and RNA polymerase IV (Pol IV) are required for DNA methylation guided by 24 nucleotide small interfering RNAs (siRNAs) in Arabidopsis thaliana [1].
AGO4 is also found, along with the DNA methyltransferase DRM2, throughout the nucleus at presumed DNA methylation target sites [1].
In Arabidopsis, except for AGO1, AGO4 and AGO7, the roles of seven other AGOs in gene silencing are not known [2].
These results suggest that AGO6 is important for the accumulation of specific heterochromatin-related siRNAs, and for DNA methylation and transcriptional gene silencing, this function is partly redundant with AGO4 [2].

Biological context of AGO4

AGO4 primarily affects non-CG methylation of the target sequences, while the IR trigger sequences lose methylation in all sequence contexts [3].
The RNA silencing gene ARGONAUTE4 (AGO4) is required for maintenance of DNA methylation at several endogenous loci and for the establishment of methylation at the FWA gene [3].
Suppression of NbAGO1 expression recapitulated the hypomorphic mutant phenotype of certain Arabidopsis (Arabidopsis thaliana) ago1 alleles, however, suppression of NbAgo4 like resulted in phenotypes differing in some respects from those reported for Arabidopsis ago4 [4].

Regulatory relationships of AGO4

We cloned ARGONAUTE4 (AGO4) from a screen for mutants that suppress silencing of the Arabidopsis SUPERMAN (SUP) gene [5].

References

An ARGONAUTE4-containing nuclear processing center colocalized with Cajal bodies in Arabidopsis thaliana. Li, C.F., Pontes, O., El-Shami, M., Henderson, I.R., Bernatavichute, Y.V., Chan, S.W., Lagrange, T., Pikaard, C.S., Jacobsen, S.E. Cell (2006) [Pubmed]
Role of Arabidopsis AGO6 in siRNA accumulation, DNA methylation and transcriptional gene silencing. Zheng, X., Zhu, J., Kapoor, A., Zhu, J.K. EMBO J. (2007) [Pubmed]
Role of Arabidopsis ARGONAUTE4 in RNA-directed DNA methylation triggered by inverted repeats. Zilberman, D., Cao, X., Johansen, L.K., Xie, Z., Carrington, J.C., Jacobsen, S.E. Curr. Biol. (2004) [Pubmed]
Virus-induced gene silencing of argonaute genes in Nicotiana benthamiana demonstrates that extensive systemic silencing requires Argonaute1-like and Argonaute4-like genes. Jones, L., Keining, T., Eamens, A., Vaistij, F.E. Plant Physiol. (2006) [Pubmed]
ARGONAUTE4 control of locus-specific siRNA accumulation and DNA and histone methylation. Zilberman, D., Cao, X., Jacobsen, S.E. Science (2003) [Pubmed]

Contributions to this collaborative article are from individual authors of WikiGenes or mined by the WikiGenes Data Mining Engine from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.About WikiGenes Open Access Licence Privacy Policy Terms of Use apsburg

Os01g0275600	Oryza sativa Japonica Group
Os04g0151800	Oryza sativa Japonica Group

The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.