Watkinson, Jonathan I. , Safaee, Natasha M. , Gillaspy, Glenda E. .
The PHD-finger is associated with chromatin-remodeling domains that function in growth and development in plants.
The plant homeodomain zinc-finger (PHD-finger) is a cysteine rich domain (C4HC3) found in numerous proteins in plants and animals. There is a lot of interest in the PHD-finger because it is strongly associated with chromatin-remodeling and two mammalian PHD-finger domains have recently been shown to bind trimethylated lysine4 of histone 3 (H3K4Me3). The domain, or a polybasic region adjacent to it, also binds specific phosphoinositides. It is likely that the domain acts as an anchor for chromatin-remodeling complexes, tethering enzymatic activities proximal to their chromatin targets.
We have completed an extensive analysis of the rice and Arabidopsis genomes and found that the PHD-finger is an abundant domain, commonly found with predicted chromatin-remodeling domains. Based on conserved residues within the PHD-finger, we were able to classify the PHD-finger domains into 2 classes. Class I is well-conserved and phylogenetic analysis supports the formation of groups within the class. Based on the presence of residues necessary to binding H3K4Me3, we have made predictions about the histone binding ability of groups in Class I. The Class II PHD-fingers are less well conserved and phylogenetic analysis is underway. The plant homologs of the mammalian Ing proteins share commonalities with both Class I and Class II PHD-fingers and are likely ligands for H3K4Me3. Loss-of-function mutants of Ing2 have abnormal floral initiation phenotypes as well as perturbations in other developmental pathways. Loss-of-function mutants of other PHD-finger containing proteins also show developmental abnormalities. The results suggest that the PHD-finger is a common domain with the potential to impact chromatin remodeling processes critical for normal growth and development of plants.
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1 - Virginia Tech, Biological Sciences, 432 Latham Hall, Ag Quad Lane, Blacksburg, VA, 24061, USA
2 - Virginia Tech, Biochemistry
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM