Two genes encoding gas vacuole proteins in Halobacterium halobium

1988 ◽  
Vol 213 (2-3) ◽  
pp. 459-464 ◽  
Author(s):  
Mary Horne ◽  
Christoph Englert ◽  
Felicitas Pfeifer
Keyword(s):  
Halobacterium Halobium ◽  
Genes Encoding ◽  
Gas Vacuole

Genome structure of Halobacterium halobium: plasmid dynamics in gas vacuole deficient mutants

1989 ◽  
Vol 35 (1) ◽  
pp. 96-100 ◽  
Author(s):  
Felicitas Pfeifer ◽  
Ulrike Blaseio ◽  
Mary Horne
Keyword(s):  
Genome Structure ◽  
Gene Mutations ◽  
Halobacterium Halobium ◽  
Chromosomal Dna ◽  
Insertion Element ◽  
Deletion Event ◽  
High Frequencies ◽  
Insertion Elements ◽  
The Difference ◽  
Gas Vacuole

Halobacterium halobium contains two gas vacuole protein genes that are located in plasmid pHH1 (p-vac) and in the chromosomal DNA (c-vac). The mutation frequency for these genes is different: the constitutively expressed p-vac gene is mutated with a frequency of 10−2, while the chromosomal gene expressed in the stationary phase of growth is mutated with a frequency of 10−5. The difference in the mutation susceptibility is due to the dynamics of plasmid pHH1. p-vac gene mutations are caused (i) by the integration of an insertion element or (ii) by a deletion event encompassing the p-vac gene region. In contrast, c-vac mutants analyzed to date incurred neither insertion elements nor deletions. Deletion events within pHH1 occur at high frequencies during the development of a H. halobium culture. The investigation of the fusion regions resulting from deletion events indicates that insertion elements are involved. The analysis of pHH1 deletion variants led to a 4 kilobase pair DNA region containing the origin of replication of the pHH1 plasmid.Key words: gas vacuole protein gene, plasmid dynamics, deletions, insertion elements.

A large plasmid from Halobacterium halobium carrying genetic information for gas vacuole formation

Plasmid ◽  
1979 ◽  
Vol 2 (3) ◽  
pp. 377-386 ◽  
Author(s):  
Gottfried Weidinger ◽  
Günther Klotz ◽  
Werner Goebel
Keyword(s):  
Genetic Information ◽  
Halobacterium Halobium ◽  
Large Plasmid ◽  
Vacuole Formation ◽  
Gas Vacuole

scholarly journals FURTHER CHARACTERIZATION OF PARTICULATE FRACTIONS FROM LYSED CELL ENVELOPES OF HALOBACTERIUM HALOBIUM AND ISOLATION OF GAS VACUOLE MEMBRANES

1968 ◽  
Vol 38 (2) ◽  
pp. 337-357 ◽  
Author(s):  
Walther Stoeckenius ◽  
Wolf H. Kunau
Keyword(s):  
Cell Wall ◽  
Cell Membrane ◽  
Cell Envelope ◽  
Buoyant Density ◽  
Halobacterium Halobium ◽  
Intracytoplasmic Membranes ◽  
High Charge Density ◽  
Fraction I ◽  
Cell Envelopes ◽  
Gas Vacuole

Lysates of cell envelopes from Halobacterium halobium have been separated into four fractions. A soluble, colorless fraction (I) containing protein, hexosamines, and no lipid is apparently derived from the cell wall. A red fraction (II), containing approximately 40 per cent lipid, 60 per cent protein, and a small amount of hexosamines consists of cell membrane disaggregated into fragments of small size. A third fraction (III) of purple color consists of large membrane sheets and has a very similar composition to II, containing the same classes of lipids but no hexosamines; its buoyant density is 1.18 g/ml. The fourth fraction (IV) has a buoyant density of 1.23 g/ml and contains the "intracytoplasmic membranes." These consist mainly of protein, and no lipid can be extracted with chloroform-methanol. Fractions I and II, which result from disaggregation of cell wall and cell membrane during lysis, contain a high proportion of dicarboxyl amino acids; this is in good agreement with the assumption that disruption of the cell envelope upon removal of salt is due to the high charge density. The intracytoplasmic membranes (IV) represent the gas vacuole membranes in the collapsed state. In a number of mutants that have lost the ability to form gas vacuoles, no vacuole membranes or any structure that could be related to them has been found.

DNA methylation in satellite repeats disorders

2019 ◽  
Vol 63 (6) ◽  
pp. 757-771 ◽  
Author(s):  
Claire Francastel ◽  
Frédérique Magdinier
Keyword(s):  
Dna Methylation ◽  
Human Genome ◽  
Repetitive Dna ◽  
Dna Sequences ◽  
Satellite Repeats ◽  
Tremendous Progress ◽  
Genes Encoding ◽  
Dna Elements ◽  
Near Future

Abstract Despite the tremendous progress made in recent years in assembling the human genome, tandemly repeated DNA elements remain poorly characterized. These sequences account for the vast majority of methylated sites in the human genome and their methylated state is necessary for this repetitive DNA to function properly and to maintain genome integrity. Furthermore, recent advances highlight the emerging role of these sequences in regulating the functions of the human genome and its variability during evolution, among individuals, or in disease susceptibility. In addition, a number of inherited rare diseases are directly linked to the alteration of some of these repetitive DNA sequences, either through changes in the organization or size of the tandem repeat arrays or through mutations in genes encoding chromatin modifiers involved in the epigenetic regulation of these elements. Although largely overlooked so far in the functional annotation of the human genome, satellite elements play key roles in its architectural and topological organization. This includes functions as boundary elements delimitating functional domains or assembly of repressive nuclear compartments, with local or distal impact on gene expression. Thus, the consideration of satellite repeats organization and their associated epigenetic landmarks, including DNA methylation (DNAme), will become unavoidable in the near future to fully decipher human phenotypes and associated diseases.

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