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Haloarchaea and the formation of gas vesicles.

Pfeifer F - Life (Basel) (2015)

Bottom Line: Halophilic Archaea (Haloarchaea) thrive in salterns containing sodium chloride concentrations up to saturation.Their synthesis depends on environmental factors, such as light, oxygen supply, temperature and salt concentration.Except for GvpI and GvpH, all of these are required to form the gas permeable wall.

View Article: PubMed Central - PubMed

Affiliation: Microbiology and Archaea, Department of Biology, Technische Universit├Ąt Darmstadt, Schnittspahnstrasse 10, 64287 Darmstadt, Germany. pfeifer@bio.tu-darmstadt.de.

ABSTRACT
Halophilic Archaea (Haloarchaea) thrive in salterns containing sodium chloride concentrations up to saturation. Many Haloarchaea possess genes encoding gas vesicles, but only a few species, such as Halobacterium salinarum and Haloferax mediterranei, produce these gas-filled, proteinaceous nanocompartments. Gas vesicles increase the buoyancy of cells and enable them to migrate vertically in the water body to regions with optimal conditions. Their synthesis depends on environmental factors, such as light, oxygen supply, temperature and salt concentration. Fourteen gas vesicle protein (gvp) genes are involved in their formation, and regulation of gvp gene expression occurs at the level of transcription, including the two regulatory proteins, GvpD and GvpE, but also at the level of translation. The gas vesicle wall is solely formed of proteins with the two major components, GvpA and GvpC, and seven additional accessory proteins are also involved. Except for GvpI and GvpH, all of these are required to form the gas permeable wall. The applications of gas vesicles include their use as an antigen presenter for viral or pathogen proteins, but also as a stable ultrasonic reporter for biomedical purposes.

No MeSH data available.


Related in: MedlinePlus

Activation of PA-PD by GvpE (a) and repression by GvpD (b). Schematic representation of the region between gvpA and gvpD and the two oppositely-oriented promoters PA and PD. TATA-box and BRE are shown in grey, and the two UAS elements are partly overlapping in the center in light grey. The reading frames gvpD and gvpA are represented by dark arrows. (a) Activation of transcription by GvpE should involve binding of GvpE, presumably as a dimer, at the respective UAS element and recruitment of TFB, TBP and of the RNA polymerase. (b) In the presence of GvpD, the interaction of GvpE-GvpD leads to a strong reduction in the amount of GvpE and the repression of gas vesicle formation.
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life-05-00385-f003: Activation of PA-PD by GvpE (a) and repression by GvpD (b). Schematic representation of the region between gvpA and gvpD and the two oppositely-oriented promoters PA and PD. TATA-box and BRE are shown in grey, and the two UAS elements are partly overlapping in the center in light grey. The reading frames gvpD and gvpA are represented by dark arrows. (a) Activation of transcription by GvpE should involve binding of GvpE, presumably as a dimer, at the respective UAS element and recruitment of TFB, TBP and of the RNA polymerase. (b) In the presence of GvpD, the interaction of GvpE-GvpD leads to a strong reduction in the amount of GvpE and the repression of gas vesicle formation.

Mentions: The presence of GvpE leads to a fast and strong activation of PpA and PpD under standard growth conditions, but as soon as GvpD appears, the activation is reduced (Figure 3). GvpD and GvpE are able to interact, and the presence of GvpD leads to an almost undetectable amount of GvpE, as determined by western analysis [36]. The reduction in the amount of GvpE was quantified using the green fluorescent protein smGFP fused to the N-terminus of GvpE [37]. The amount of GFP-GvpE is more than 60% reduced in the presence of GvpD. The fact that a reduction in the amount of GvpE is not observed in the presence of the repression defective GvpDMut6 mutant underlines that a functional GvpD is required for this process [37].


Haloarchaea and the formation of gas vesicles.

Pfeifer F - Life (Basel) (2015)

Activation of PA-PD by GvpE (a) and repression by GvpD (b). Schematic representation of the region between gvpA and gvpD and the two oppositely-oriented promoters PA and PD. TATA-box and BRE are shown in grey, and the two UAS elements are partly overlapping in the center in light grey. The reading frames gvpD and gvpA are represented by dark arrows. (a) Activation of transcription by GvpE should involve binding of GvpE, presumably as a dimer, at the respective UAS element and recruitment of TFB, TBP and of the RNA polymerase. (b) In the presence of GvpD, the interaction of GvpE-GvpD leads to a strong reduction in the amount of GvpE and the repression of gas vesicle formation.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4390858&req=5

life-05-00385-f003: Activation of PA-PD by GvpE (a) and repression by GvpD (b). Schematic representation of the region between gvpA and gvpD and the two oppositely-oriented promoters PA and PD. TATA-box and BRE are shown in grey, and the two UAS elements are partly overlapping in the center in light grey. The reading frames gvpD and gvpA are represented by dark arrows. (a) Activation of transcription by GvpE should involve binding of GvpE, presumably as a dimer, at the respective UAS element and recruitment of TFB, TBP and of the RNA polymerase. (b) In the presence of GvpD, the interaction of GvpE-GvpD leads to a strong reduction in the amount of GvpE and the repression of gas vesicle formation.
Mentions: The presence of GvpE leads to a fast and strong activation of PpA and PpD under standard growth conditions, but as soon as GvpD appears, the activation is reduced (Figure 3). GvpD and GvpE are able to interact, and the presence of GvpD leads to an almost undetectable amount of GvpE, as determined by western analysis [36]. The reduction in the amount of GvpE was quantified using the green fluorescent protein smGFP fused to the N-terminus of GvpE [37]. The amount of GFP-GvpE is more than 60% reduced in the presence of GvpD. The fact that a reduction in the amount of GvpE is not observed in the presence of the repression defective GvpDMut6 mutant underlines that a functional GvpD is required for this process [37].

Bottom Line: Halophilic Archaea (Haloarchaea) thrive in salterns containing sodium chloride concentrations up to saturation.Their synthesis depends on environmental factors, such as light, oxygen supply, temperature and salt concentration.Except for GvpI and GvpH, all of these are required to form the gas permeable wall.

View Article: PubMed Central - PubMed

Affiliation: Microbiology and Archaea, Department of Biology, Technische Universit├Ąt Darmstadt, Schnittspahnstrasse 10, 64287 Darmstadt, Germany. pfeifer@bio.tu-darmstadt.de.

ABSTRACT
Halophilic Archaea (Haloarchaea) thrive in salterns containing sodium chloride concentrations up to saturation. Many Haloarchaea possess genes encoding gas vesicles, but only a few species, such as Halobacterium salinarum and Haloferax mediterranei, produce these gas-filled, proteinaceous nanocompartments. Gas vesicles increase the buoyancy of cells and enable them to migrate vertically in the water body to regions with optimal conditions. Their synthesis depends on environmental factors, such as light, oxygen supply, temperature and salt concentration. Fourteen gas vesicle protein (gvp) genes are involved in their formation, and regulation of gvp gene expression occurs at the level of transcription, including the two regulatory proteins, GvpD and GvpE, but also at the level of translation. The gas vesicle wall is solely formed of proteins with the two major components, GvpA and GvpC, and seven additional accessory proteins are also involved. Except for GvpI and GvpH, all of these are required to form the gas permeable wall. The applications of gas vesicles include their use as an antigen presenter for viral or pathogen proteins, but also as a stable ultrasonic reporter for biomedical purposes.

No MeSH data available.


Related in: MedlinePlus