Disease relevance of ho1

• This gene, named ho1, was cloned and expressed in Escherichia coli under the control of the lacZ promoter [1].
• Two paralogs of ho (ho1 and ho2) have been identified in the genome of the cyanobacterium, Synechocystis sp. PCC 6803 [2].
• This construct was placed in a binary plasmid vectorcontaining a kanamycin resistance marker and a cauliflower mosaic virus 35S promoter to control expression of the chimeric oli-ho1 gene and used to transform A. thaliana hy1 plants [3].
• In cyanobacteria, red algae, and cryptophyceae, HO is a key enzyme in the synthesis of the chromophoric part of the photosynthetic antennae [4].

High impact information on ho1

• The phytobilin chromophores of phycobiliproteins and phytochromes are biosynthesized from heme in a pathway that begins with the opening of the tetrapyrrole macrocycle of protoheme to form biliverdin IX alpha, in a reaction catalyzed by heme oxygenase [1].
• The open reading frame of ho1 was fused in frame with a chloroplast transit peptide-encoding sequence from the oli gene of Antirrhinum majus [3].
• Carbon monoxide (CO) is produced during the heme catabolism by heme oxygenase [5].
• An efficient bacterial expression system of cyanobacterium Synechocystis sp. PCC 6803 heme oxygenase gene, ho-1, has been constructed, using a synthetic gene [6].
• Two isoforms of a heme oxygenase gene, ho1 and ho2, with 51% identity in amino acid sequence have been identified in the cyanobacterium Synechocystis sp. PCC 6803 [7].

Analytical, diagnostic and therapeutic context of ho1

• Heme oxygenase activity was not sedimented by centrifugation at 100, 000 g [1].

References