High impact information on PAI2

• Revertant lines display coordinately reduced methylation of both PAI2 and PAI3, implying that this hypomethylation acts in a concerted manner across the genome rather than at individual sites [1].
• The progressive loss of fluorescence correlated with a progressive loss of methylation from the PAI2 gene [2].
• In order to elucidate the factors that control genomic DNA methylation patterning, a genetic screen for mutations that disrupt methylation-correlated silencing of the endogenous gene PAI2 was conducted in Arabidopsis: This screen yielded seven loss-of-function alleles in a SET domain protein with histone H3 Lys9 methyltransferase activity, SUVH4 [3].
• DNA sequence analysis of cDNA and genomic clones indicated that the PAI1 and PAI2 [4].
• Yeast artificial chromosome hybridization studies indicated that the PAI2 gene is tightly linked to the anthranilate synthase alpha subunit 1 (ASA1) gene on chromosome 5 [4].

Biological context of PAI2

• In contrast, SUVH6 does not play a significant role in maintenance of H3 K9 or DNA methylation on PAI2, transposon sequences, or centromere repeat sequences [5].
• To determine the relationship between partial methylation and expression for the singlet PAI2 gene we constructed a novel reporter strain of Arabidopsis in which PAI2 silencing could be monitored by a blue fluorescent plant phenotype diagnostic of tryptophan pathway defects [6].

Associations of PAI2 with chemical compounds

• The mutations conferred reduced cytosine methylation on PAI2, especially in non-CG sequence contexts, but did not affect methylation on another PAI locus carrying two genes arranged as an inverted repeat [3].
• Previous analysis of the PAI tryptophan biosynthetic gene family in Arabidopsis thaliana revealed that the Wassilewskija (WS) ecotype has four PAI genes at three unlinked sites: a tail-to-tail inverted repeat at one locus (PAI1-PAI4) plus singlet genes at two other loci (PAI2 and PAI3) [7].

Other interactions of PAI2

• The extreme nucleotide conservation between the unlinked PAI1 and PAI2 loci suggests that this gene family is actively evolving [4].
• Both PAI1 and PAI3 showed approximately 10-fold stronger expression than PAI2 [8].

References