EC Number   |
General Information |
Reference |
|---|
   2.1.1.369 | physiological function |
ATXR5 selectively methylates the replication-dependent histone H3 variant H3.1. ATXR5 contains a bipartite catalytic domain that specifically reads alanine-31 of H3.1. Variation at position 31 between H3.1 and replication-independent H3.3 is conserved in plants and animals, and threonine-31 in H3.3 is responsible for inhibiting the activity of ATXR5 and its paralog, ATXR6 |
760193 |
| 2.1.1.369 | physiological function |
ATXR6 associates with proliferating cell nuclear antigen PCNA, and PCNA inhibits ATXR6 enzymatic activity. A trio of hydrophobic residues contributes to the binding of the enzyme to the sliding clamp of PCNA. ATXR6 PIP motif participates in the binding of PCNA and two molecules of ATXR6 bind to a trimer of PCNA likely enabling the recruitment of a third protein to the sliding clamp |
759627 |
| 2.1.1.369 | physiological function |
isoform ATXR5 discriminates between histone H3 variants and preferentially methylates K27 on histone H3.1. ATXR5 preferentially methylates the R/F-K*-S/C-G/A-P/C motif with striking preference for hydrophobic and aromatic residues in positions flanking this core of five amino acids. Posttranscriptional modifications of residues neighboring K27 that are typically associated with actively transcribed chromatin are detrimental to ATXR5 activity. The ATXR5 PHD domain employs a narrow binding pocket to selectively recognize unmethylated K4 of histone H3. Deletion or mutation of the PHD domain reduces the catalytic efficiency of ATXR5 up to 58fold |
759862 |
| 2.1.1.369 | physiological function |
isoforms ATXR5 and ATXR6 exhibit histone H3K27 monomethyltransferase activity and double mutants have reduced H3K27me1 levels in vivo and show partial heterochromatin decondensation. Mutations in Atxr5 and Atxr6 also lead to transcriptional activation of repressed heterochromatic elements. H3K9me2 and DNA methylation are unaffected in the double mutant |
757787 |
| 2.1.1.369 | physiological function |
isoforms ATXR5 and ATXR6 interact with RNA metabolism component serrate. Serrate binds to ATXR5/6-regulated transposable elements loci and promotes H3K27me1 accumulation in these regions. Serrate directly enhances ATXR5 enzymatic activity in vitro. Serrate mutation suppresses the transposable elements reactivation and DNA rereplication phenotypes in the Atxr5/Atxr6 mutant through RDR6 |
759111 |
| 2.1.1.369 | physiological function |
mutation of isoforms ATXR5 and ATXR6 lead to rereplication of specific genomic locations, the vast majority of which correspond to transposons and other repetitive and silent elements of the Arabidopsis genome. These sites also correspond to high levels of H3K27 monomethylation. Mutation of ATXR5 and ATXR6 also causes upregulation of transposon expression and has pleiotropic effects on plant development |
759844 |
| 2.1.1.369 | physiological function |
mutation of isoforms ATXR5 and ATXR6 lead to rereplication of specific genomic locations, the vast majority of which correspond to transposons and other repetitive and silent elements of the Arabidopsis genome. These sites also correspond to high levels of H3K27 monomethylation. Mutation of ATXR5 and ATXR6 also causes upregulation of transposon expression and has pleiotropic effects on plant development. The PIP motif, PHD and SET domains are all required for ATXR6 activity |
759844 |
