Disease relevance of PDS1

• We investigated the biochemical characteristics of this 4HPPD by overproducing the recombinant protein in Escherichia coli JM105 [1].
• The subcellular localization of the recombinant 4HPPD in chlorophyllous tissues was examined by overexpressing its complete coding sequence in transgenic tobacco (Nicotiana tabacum), using Agrobacterium tumefaciens transformation [1].

High impact information on PDS1

• We propose a model in which IM function is linked to phytoene desaturation and, possibly, to the respiratory activity of the chloroplast [2].
• Genetic dissection of carotenoid synthesis in arabidopsis defines plastoquinone as an essential component of phytoene desaturation [3].
• Here, we report the identification and characterization of two nonallelic albino mutations, pds1 and pds2 (for phytoene desaturation), that are disrupted in phytoene desaturation and as a result accumulate phytoene, the first C40 compound of the pathway [3].
• The pds1 mutation affects the enzyme 4-hydroxyphenylpyruvate dioxygenase because it can be rescued by growth on the product but not the substrate of this enzyme, homogentisic acid and 4-hydroxyphenylpyruvate, respectively [3].
• Surprisingly, neither mutation maps to the locus encoding the phytoene desaturase enzyme, indicating that the products of at least three loci are required for phytoene desaturation in higher plants [3].

Chemical compound and disease context of PDS1

• Expression of pHPPD in E. coli catalyzes the accumulation of homogentisic acid, indicating that it encodes a functional HPPDase enzyme [4].

Anatomical context of PDS1

• These analyses clearly revealed that 4HPPD was confined to the cytosol compartment, not targeted to the chloroplast [1].

Associations of PDS1 with chemical compounds

• Mutation of the PDS1 locus disrupts the activity of p-hydroxyphenylpyruvate dioxygenase (HPPDase), the first committed step in the synthesis of both plastoquinone and tocopherols in plants [4].
• Analysis of pds1 and pds2 shows that both mutants are plastoquinone and tocopherol deficient, in addition to their inability to desaturate phytoene [3].
• The transformation of 4-hydroxyphenylpyruvate to homogentisate, catalyzed by 4-hydroxyphenylpyruvate dioxygenase (HPPD), plays an important role in degrading aromatic amino acids [5].
• Because the white sectors of im accumulate the noncolored carotenoid, phytoene, IM likely serves as a redox component in phytoene desaturation [6].
• This was achieved by the expression of the yeast (Saccharomyces cerevisiae) prephenate dehydrogenase gene in tobacco (Nicotiana tabacum) plants that already overexpress the Arabidopsis p-hydroxyphenylpyruvate dioxygenase coding sequence [7].

Analytical, diagnostic and therapeutic context of PDS1

• First, the amount of genomic DNA in the extracts, obtained from an individual A. thaliana transformant, was accurately determined by the 1st competitive PCR using a known single copy gene, 4HPPD (4-hydroxyphenylpyruvate dioxygenase), as a target [8].

References