Molecular basis of inherited disorders of collagen biosynthesis: implications for prenatal diagnosis.
Explore the source record for details and available documents.
Collagen Diseases↗
Biomedical subjects
D H Cohn
Publications and source records attributed to D H Cohn.
Luciferase genes cloned from the unculturable luminous bacteroid symbiont of the Caribbean flashlight fish, Kryptophanaron alfredi.
Light organs of anomalopid (flashlight) fish contain luminous bacteroids that have never been cultured and, consequently, have been difficult to study. We have characterized the luciferase (lux) region of DNA extracted from light organs of the Caribbean flashlight fish Kryptophanaron alfredi by hybridization of cloned Vibrio harveyi lux genes to restriction-endonuclease-digested, light organ DNA. Comparison of the hybridization pattern of light organ DNA with that of DNA of a putative symbiotic isolate provides a method for identifying the authentic luminous symbiont regardless of its luminescence, and was used to reject one such isolate. Light organ DNA was further used to construct a cosmid clone bank and the luciferase genes were isolated. Unlike other bacterial luciferase genes, the genes were not expressed in Escherichia coli. When placed under the control of the E. coli trp promoter, the genes were transcribed but no luciferase was detected, suggesting a posttranscriptional block to expression.
Animals↗
Lethal osteogenesis imperfecta resulting from a single nucleotide change in one human pro alpha 1(I) collagen allele.
We have characterized a mutation in a pro alpha 1(I) procollagen gene (COL1A1) that results in lethal (type II) osteogenesis imperfecta. The mutation is a single base change that results in a cysteine-for-glycine substitution at position 988 of the triple-helical portion of half of the alpha 1(I) chains of type I collagen. The mutation thus disrupts the (Gly-Xaa-Yaa)n pattern necessary for triple-helix formation, where Xaa and Yaa are other amino acids. These experiments establish the minimal mutation in a type I collagen gene capable of producing lethal disease, and the lethality demonstrates a selective mechanism for the stringent maintenance of the collagen gene structure.
Alleles↗
Nucleotide sequence of the luxA gene of Vibrio harveyi and the complete amino acid sequence of the alpha subunit of bacterial luciferase.
The nucleotide sequence of the 1.85-kilobase EcoRI fragment from Vibrio harveyi that was cloned using a mixed-sequence synthetic oligonucleotide probe (Cohn, D. H., Ogden, R. C., Abelson, J. N., Baldwin, T. O., Nealson, K. H., Simon, M. I., and Mileham, A. J. (1983) Proc. Natl. Acad. Sci. U.S.A. 80, 120-123) has been determined. The alpha subunit-coding region (luxA) was found to begin at base number 707 and end at base number 1771. The alpha subunit has a calculated molecular weight of 40,108 and comprises a total of 355 amino acid residues. There are 34 base pairs separating the start of the alpha subunit structural gene and a 669-base open reading frame extending from the proximal EcoRI site. At the 3' end of the luxA coding region there are 26 bases between the end of the structural gene and the start of the luxB structural gene. Approximately two-thirds of the alpha subunit was sequenced by protein chemical techniques. The amino acid sequence implied by the DNA sequence, with few exceptions, confirmed the chemically determined sequence. Regions of the alpha subunit thought to comprise the active center were found to reside in two discrete and relatively basic regions, one from around residues 100-115 and the second from around residues 280-295.
Amino Acid Sequence↗
Cloning of the Vibrio harveyi luciferase genes: use of a synthetic oligonucleotide probe.
A mixed-sequence synthetic oligonucleotide probe was used to isolate a clone containing the gene encoding the alpha subunit of bacterial luciferase from Vibrio harveyi and part of the gene coding for the beta subunit. DNA sequence analysis has allowed us to determine that the genes are closely linked on the bacterial chromosome and transcribed in the same direction. Comparison of the sequences in the regions preceding the two structural genes has revealed considerable homology and has identified sites that may be involved in the expression of the genes. Identification of a clone from a clone bank of total genomic DNA from this organism shows that mixed probes can be successfully used to isolate a gene of interest from any bacterium provided some protein sequence for the gene product is available.
Amino Acid Sequence↗