Disease relevance of orf1

• A region containing bent DNA (Bent 111), previously mapped to 52.6 min of the E. coli chromosome, was discovered in the 5' region of orf1 [1].
• The amino acid sequence of the orf1 product was similar to that of the aromatic hydrocarbon transporter gene (pcaK) in Pseudomonas putida PRS2000 [2].
• In addition, the orf1 gene of Aeromonas hydrophila was found to play a critical role in assimilating the 3HV monomer and in regulating the monomer fraction in the terpolymer [3].
• In fact, Salmonella and Escherichia coli strains carrying pRF-1 were found to show strong resistance to sulfathiazole, suggesting that orf1 is a functional gene [4].
• The proteins encoded by orf1 and orf2 show the highest degree of similarity with similarly arranged peptide sequences translated from Corynebacterium glutamicum pXZ10142 and Mycobacterium fortuitum pAL5000 plasmids [5].

High impact information on orf1

• Shotgun cloning experiments with restriction enzyme-digested genomic DNA from Morganella morganii 1, which expresses high levels of cephalosporinase, into the pBKCMV cloning vector gave a recombinant plasmid, pPON-1, which encoded four entire genes: ampC, ampR, an hybF family gene, and orf-1 of unknown function [6].
• Through the use of transcriptional fusions, none of the putative tol (or tol-associated) genes were shown to be regulated by PhoPQ, bile, or the RcsC-RcsB two-component system; however, all of the genes (orfX, orf1, tolQRA) are predicted to be cotranscribed [7].
• Two other genes (orf1 and orf6) conferring utilization of 4-hydroxybutyrate were identified during subcloning and sequencing of the inserts of pAH1 and pAH3 [8].
• These ORFs were designated cpsIaA to cpsIaL, neu (neuraminic acid synthesis gene) A to D, orf1 and ung (uracil DNA glycosylase) [9].
• DNA sequence analysis showed that there were two transcriptional terminators in the 3' end of this operon (downstream of orf1 and ung) [9].

Biological context of orf1

• The functions of orf1 and orf3 remain unknown. orf1 contains multiple tandem repeats of the tetrameric DNA sequence CAAT near the 5' end [10].
• The oriT site was found upstream of six open reading frames (orf1 to orf6), each of which plays a role in conjugal transfer [11].
• Unlike the cps gene cluster of S. pneumoniae serotype 14, transcription of this operon may start from cpsIaA, cpsIaE, and orf1 because putative promoter sequences were found in front of these genes [9].
• The region comprising orf1 and orf2 displayed a strikingly low G+C content and was present exclusively in C. glutamicum strains [12].
• Primer extension experiments revealed a strong transcription initiation site upstream of orf1 [1].

Associations of orf1 with chemical compounds

• The lack of polymerization of the K40 polysaccharide indicates that orf1 encodes the K40 polymerase (Wzy) and that assembly of the K40 polysaccharide occurs via a Wzy-dependent pathway (in contrast to that of the O8 polysaccharide) [13].
• A third gene (morC), exhibiting sequence identity to known reductases, and a fourth truncated gene encoding a putative glutamine reductase (orf1' ), were found downstream of morB [14].

Other interactions of orf1

• Gene disruption experiments with the wild type proved that orf1 is essential for complementation, but inactivation of orf2 also resulted in a small but significant increase in fertility [12].
• Expression of the genes was negatively regulated by the product of orf1, now called merR [15].
• The products of two other ORFs showed similarity to GlnP of Escherichia coli (orf1) and beta-glucosidase A of B. polymyxa (orf5) [16].
• The GC contents of orf1, orf12 and orf14 to orf26 were similar to the overall GC content of the E. coli chromosome (51%) [17].

Analytical, diagnostic and therapeutic context of orf1

• Here, we demonstrate that insertional inactivation of orf1 results in the accumulation of a semirough (SR)-K40LPS form which retains reactivity with specific polyclonal serum in Western immunoblots [13].
• Sequence analysis revealed the presence of two open reading frames (orf1 and orf2) on the complementing DNA fragment [12].

References