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.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)



Gene Review


Arabidopsis thaliana

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.

Disease relevance of GUN4

  • Here we report a 1.78-A resolution crystal structure of Synechocystis GUN4, in which the porphyrin-binding domain adopts a unique three dimensional fold with a "cupped hand" shape [1].

High impact information on GUN4

  • There is a reduction of chlorophyll accumulation in gun4 and gun5 mutant plants, and a gun4gun5 double mutant shows an albino phenotype [2].
  • GUN5 is the ChlH subunit of Mg-chelatase, which produces Mg-Proto, and GUN4 is a regulator of ChlH activity (2) [3].
  • Ycf53 is a hypothetical chloroplast open reading frame with similarity to the Arabidopsis nuclear gene GUN4 [4].
  • Accumulation of magnesium-protoporphyrin IX (Mg-Proto), an intermediate in chlorophyll biosynthesis, is a plastid signal that represses nuclear transcription through a signaling pathway that, in Arabidopsis, requires the GUN4 gene [5].


  1. Structure of the Mg-chelatase cofactor GUN4 reveals a novel hand-shaped fold for porphyrin binding. Verdecia, M.A., Larkin, R.M., Ferrer, J.L., Riek, R., Chory, J., Noel, J.P. PLoS Biol. (2005) [Pubmed]
  2. Arabidopsis genomes uncoupled 5 (GUN5) mutant reveals the involvement of Mg-chelatase H subunit in plastid-to-nucleus signal transduction. Mochizuki, N., Brusslan, J.A., Larkin, R., Nagatani, A., Chory, J. Proc. Natl. Acad. Sci. U.S.A. (2001) [Pubmed]
  3. Pathways of intracellular communication: tetrapyrroles and plastid-to-nucleus signaling. Rodermel, S., Park, S. Bioessays (2003) [Pubmed]
  4. The gun4 gene is essential for cyanobacterial porphyrin metabolism. Wilde, A., Mikolajczyk, S., Alawady, A., Lokstein, H., Grimm, B. FEBS Lett. (2004) [Pubmed]
  5. GUN4, a regulator of chlorophyll synthesis and intracellular signaling. Larkin, R.M., Alonso, J.M., Ecker, J.R., Chory, J. Science (2003) [Pubmed]
WikiGenes - Universities