The highly similar Arabidopsis homologs of trithorax ATX1 and ATX2 encode proteins with divergent biochemical functions.
Gene duplication followed by functional specialization is a potent force in the evolution of biological diversity. A comparative study of two highly conserved duplicated genes, ARABIDOPSIS TRITHORAX-LIKE PROTEIN1 (ATX1) and ATX2, revealed features of both partial redundancy and of functional divergence. Although structurally similar, their regulatory sequences have diverged, resulting in distinct temporal and spatial patterns of expression of the ATX1 and ATX2 genes. We found that ATX2 methylates only a limited fraction of nucleosomes and that ATX1 and ATX2 influence the expression of largely nonoverlapping gene sets. Even when coregulating shared targets, ATX1 and ATX2 may employ different mechanisms. Most remarkable is the divergence of their biochemical activities: both proteins methylate K4 of histone H3, but while ATX1 trimethylates it, ATX2 dimethylates it. ATX2 and ATX1 provide an example of separated K4 di from K4 trimethyltransferase activity.
Saleh
Abdelaty
A
School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588-0118, USA.
Alvarez-Venegas
Raul
R
Yilmaz
Mehtap
M
Le
Oahn
O
Hou
Guichuan
G
Sadder
Monther
M
Al-Abdallat
Ayed
A
Xia
Yuannan
Y
Lu
Guoqinq
G
Ladunga
Istvan
I
Avramova
Zoya
Z
D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D047369:Chromatin Immunoprecipitation; D018506:Gene Expression Regulation, Plant; D020131:Genes, Duplicate; D011495:Histone-Lysine N-Methyltransferase; D006657:Histones / Q000378:metabolism; D008745:Methylation; D008957:Models, Genetic; D009707:Nucleosomes / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism / Q000502:physiology
D029681:Arabidopsis Proteins; D006657:Histones; D009707:Nucleosomes; D020033:Protein Isoforms; D014157:Transcription Factors; C504056:At2g31650 protein, Arabidopsis; D011495:Histone-Lysine N-Methyltransferase