vitamin-k-semiquinone-radical and Chromosome-Deletion

A terminal deletion in the short arm of chromosome 8 was found in a 2.5-year-old boy: 46,XY,del(8) (p22.0) and in a 1-year-old girl: 46,XX,del(8) (p23.1) with dysmorphic craniofacial features and developmental retardation. Erythrocyte GSR activities of the boy and of his parents were within normal limits. Vitamin K dependent coagulation factors in the girl and her parents gave normal results. Clinical findings were compared with previously reported cases and suggested a recognizable syndrome.

Topics: Child, Preschool; Chromosome Banding; Chromosome Deletion; Chromosomes, Human, Pair 8; Facial Expression; Female; Humans; Infant; Karyotyping; Male; Monosomy; Vitamin K

In Escherichia coli, the biosynthesis of the electron carrier menaquinone (vitamin K2) involves at least seven identified enzymes. One of these, naphthoate synthase, forms the bicyclic ring system by catalyzing the conversion of o-succinylbenzoyl-coenzyme A to 1,4-dihydroxy-2-naphthoic acid. The gene for this enzyme has been previously identified as menB. By genetic and biochemical tests, a 1.349-kb DNA fragment from the E. coli men locus complements menB mutants. This fragment contains a single 285-codon open reading frame (ORF). Recombinant plasmids containing deletions of either the amino or the carboxy region of the ORF fail to complement the mutants. The ORF is preceded by consensus sequences for a ribosomal binding site and a sigma 70 promoter. menB transcription sufficient to complement the menB mutant in vivo and in vitro can be initiated from the identified putative promoter, and that in the constructs, menB expression, can be made independent of read-through transcription from the lac promoter. However, multicopy plasmids containing menB fail to generate the expected levels of enzymatic activity.

Topics: Amino Acid Sequence; Base Sequence; Chromosome Deletion; Cloning, Molecular; Escherichia coli; Gene Expression; Genes, Bacterial; Molecular Sequence Data; Plasmids; Promoter Regions, Genetic; Vitamin K

We report on a male infant with X-linked ichthyosis, X-linked Kallmann syndrome, and X-linked recessive chondrodysplasia punctata (CPXR). Chromosome analysis showed a terminal deletion with a breakpoint at Xp22.31, inherited maternally. This patient confirms the localization of XLI, XLK, and CPXR to this region of the X chromosome and represents an example of a "contiguous gene syndrome." A comparison of the manifestations of patients with CPXR, warfarin embryopathy, and vitamin K epoxide reductase deficiency shows a remarkable similarity. However, vitamin K epoxide reductase deficiency does not appear to be the cause of CPXR. We propose that CPXR may be due to a defect in a vitamin K-dependent bone protein such as vitamin K-dependent bone carboxylase, osteocalcin, or matrix Gla protein.

Topics: Chondrodysplasia Punctata; Chromosome Deletion; Chromosome Mapping; Genetic Linkage; Humans; Hypogonadism; Ichthyosis; Infant; Male; Mixed Function Oxygenases; Olfaction Disorders; Olfactory Bulb; Sulfatases; Syndrome; Vitamin K; Vitamin K Epoxide Reductases; X Chromosome

Menaquinone (men) mutants of Salmonella typhimurium isolated on the basis of their inability to produce trimethylamine were characterized with respect to mutation site, the ability to cross-feed each other and be cross-fed by known Escherichia coli men mutants, and response to intermediates of the menaquinone biosynthetic pathway. Cross-feeding tests were based on the requirement of menaquinone for hydrogen sulfide production. Genotypes corresponding to the menA, B, C, D, and possibly E genes described in E. coli were all identified. Additional studies of deletions in the menBCD area revealed that this cluster lies between ack/pta and glpT, as in E. coli. The ack and pta mutants were also defective in the production of trimethylamine and failed to produce gas in the absence of added formate.

Topics: Chromosome Deletion; Chromosome Mapping; Escherichia coli; Genes; Genes, Bacterial; Mutation; Phenotype; Salmonella typhimurium; Species Specificity; Vitamin K