scholarly journals Identification of Diverse Archaeal Proteins with Class III Signal Peptides Cleaved by Distinct Archaeal Prepilin Peptidases

2006 ◽  
Vol 189 (3) ◽  
pp. 772-778 ◽  
Author(s):  
Zalán Szabó ◽  
Adriana Oliveira Stahl ◽  
Sonja-V. Albers ◽  
Jessica C. Kissinger ◽  
Arnold J. M. Driessen ◽  
...  
Keyword(s):  
Signal Peptidase ◽  
Signal Peptides ◽  
Class Iii ◽  
Methanococcus Maripaludis ◽  
Gene Encoding ◽  
Hydrophobic Domain ◽  
Type Iv ◽  
Cell Surface Structures ◽  
Genes Encoding ◽  
Processing Site

ABSTRACT Most secreted archaeal proteins are targeted to the membrane via a tripartite signal composed of a charged N terminus and a hydrophobic domain, followed by a signal peptidase-processing site. Signal peptides of archaeal flagellins, similar to class III signal peptides of bacterial type IV pilins, are distinct in that their processing sites precede the hydrophobic domain, which is crucial for assembly of these extracytoplasmic structures. To identify the complement of archaeal proteins with class III signal sequences, a PERL program (FlaFind) was written. A diverse set of proteins was identified, and many of these FlaFind positives were encoded by genes that were cotranscribed with homologs of pilus assembly genes. Moreover, structural conservation of primary sequences between many FlaFind positives and subunits of bacterial pilus-like structures, which have been shown to be critical for pilin assembly, have been observed. A subset of pilin-like FlaFind positives contained a conserved domain of unknown function (DUF361) within the signal peptide. Many of the genes encoding these proteins were in operons that contained a gene encoding a novel euryarchaeal prepilin-peptidase, EppA, homolog. Heterologous analysis revealed that Methanococcus maripaludis DUF361-containing proteins were specifically processed by the EppA homolog of this archaeon. Conversely, M. maripaludis preflagellins were cleaved only by the archaeal preflagellin peptidase FlaK. Together, the results reveal a diverse set of archaeal proteins with class III signal peptides that might be subunits of as-yet-undescribed cell surface structures, such as archaeal pili.

scholarly journals Mls is not a single gene, allelic system. Different stimulatory Mls determinants are the products of at least two nonallelic, unlinked genes.

1987 ◽  
Vol 166 (4) ◽  
pp. 1150-1155 ◽  
Author(s):  
R Abe ◽  
J J Ryan ◽  
R J Hodes
Keyword(s):  
T Cells ◽  
Single Gene ◽  
Surface Structures ◽  
Chromosome 1 ◽  
Gene Products ◽  
Spleen Cells ◽  
Gene Encoding ◽  
Cell Surface Structures ◽  
Genes Encoding ◽  
Polymorphic Cell

Mls determinants share with MHC products the unique property of stimulating T cells at extraordinarily high precursor frequencies. The Mls system was originally described as a single locus on chromosome 1, with four alleles, Mlsa, Mlsb, Mlsc, and Mlsd, that encode polymorphic cell surface structures. However, the fundamental issues of polymorphism and allelism in the Mls system remain controversial. To clarify these questions, a formal segregation analysis of the genes encoding Mlsa and Mlsc determinants was carried out by testing the capacity of spleen cells from progeny of (Mlsa X Mlsc)F1 X Mlsb breedings to stimulate responses by unprimed T cells and by Mlsa- and Mlsc-specific cloned T cells. The results of this analysis indicated that the gene encoding Mlsa determinants is neither allelic to nor linked to the gene encoding Mlsc determinants. Together with previous findings, these results also suggest that another strongly stimulatory type, Mlsd, in fact results from the independent expression of unlinked Mlsa and Mlsc gene products. Based on these observations, it is concluded that, contrary to conventional concepts, the stimulatory phenotypes designated as Mlsa, Mlsc, and Mlsd can be accounted for by the independent expression of the products of at least two unlinked gene loci.

scholarly journals Biosynthesis and Role of N-Linked Glycosylation in Cell Surface Structures of Archaea with a Focus on Flagella and S Layers

2010 ◽  
Vol 2010 ◽  
pp. 1-20 ◽  
Author(s):  
Ken F. Jarrell ◽  
Gareth M. Jones ◽  
Divya B. Nair
Keyword(s):  
Surface Structures ◽  
Model Organisms ◽  
Glycan Structure ◽  
Methanococcus Maripaludis ◽  
The Past ◽  
Cell Surface Structures ◽  
Layer Function ◽  
Successful Isolation ◽  
Genes Encoding

The genetics and biochemistry of the N-linked glycosylation system of Archaea have been investigated over the past 5 years using flagellins and S layers as reporter proteins in the model organisms,Methanococcus voltae, Methanococcus maripaludis,andHaloferax volcanii. Structures of archaeal N-linked glycans have indicated a variety of linking sugars as well as unique sugar components. InM. voltae, M. maripaludis,andH. volcanii, a number of archaeal glycosylation genes (agl) have been identified by deletion and complementation studies. These include many of the glycosyltransferases and the oligosaccharyltransferase needed to assemble the glycans as well as some of the genes encoding enzymes required for the biosynthesis of the sugars themselves. The N-linked glycosylation system is not essential for any ofM. voltae, M. maripaludis,orH. volcanii, as demonstrated by the successful isolation of mutants carrying deletions in the oligosaccharyltransferase geneaglB(a homologue of the eukaryotic Stt3 subunit of the oligosaccharyltransferase complex). However, mutations that affect the glycan structure have serious effects on both flagellation and S layer function.

scholarly journals Different Minimal Signal Peptide Lengths Recognized by the Archaeal Prepilin-Like Peptidases FlaK and PibD

2008 ◽  
Vol 191 (21) ◽  
pp. 6732-6740 ◽  
Author(s):  
Sandy Y. M. Ng ◽  
David J. VanDyke ◽  
Bonnie Chaban ◽  
John Wu ◽  
Yoshika Nosaka ◽  
...  
Keyword(s):  
Amino Acids ◽  
Signal Peptide ◽  
Signal Peptidase ◽  
Signal Peptides ◽  
Peptidase Activity ◽  
Vitro Assay ◽  
Type Iv ◽  
Peptide Length ◽  
Short Signal

ABSTRACT In Archaea, the preflagellin peptidase (a type IV prepilin-like peptidase designated FlaK in Methanococcus voltae and Methanococcus maripaludis) is the enzyme that cleaves the N-terminal signal peptide from preflagellins. In methanogens and several other archaeal species, the typical flagellin signal peptide length is 11 to 12 amino acids, while in other archaea preflagellins possess extremely short signal peptides. A systematic approach to address the signal peptide length requirement for preflagellin processing is presented in this study. M. voltae preflagellin FlaB2 proteins with signal peptides 3 to 12 amino acids in length were generated and used as a substrate in an in vitro assay utilizing M. voltae membranes as an enzyme source. Processing by FlaK was observed in FlaB2 proteins containing signal peptides shortened to 5 amino acids; signal peptides 4 or 3 amino acids in length were unprocessed. In the case of Sulfolobus solfataricus, where the preflagellin peptidase PibD has broader substrate specificity, some predicted substrates have predicted signal peptides as short as 3 amino acids. Interestingly, the shorter signal peptides of the various mutant FlaB2 proteins not processed by FlaK were processed by PibD, suggesting that some archaeal preflagellin peptidases are likely adapted toward cleaving shorter signal peptides. The functional complementation of signal peptidase activity by FlaK and PibD in an M. maripaludis ΔflaK mutant indicated that processing of preflagellins was detected by complementation with either FlaK or PibD, yet only FlaK-complemented cells were flagellated. This suggested that a block in an assembly step subsequent to signal peptide removal occurred in the PibD complementation.

scholarly journals Construction of a complete set of Neisseria meningitidis mutants and its use for the phenotypic profiling of this human pathogen

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Alastair Muir ◽  
Ishwori Gurung ◽  
Ana Cehovin ◽  
Adelme Bazin ◽  
David Vallenet ◽  
...  
Keyword(s):  
Neisseria Meningitidis ◽  
Bacterial Pathogen ◽  
Essential Genes ◽  
Gene Encoding ◽  
Complete Collection ◽  
Protein Coding ◽  
Type Iv ◽  
Membrane Structure And Function ◽  
Genes Encoding ◽  
Information Cell

Abstract The bacterium Neisseria meningitidis causes life-threatening meningitis and sepsis. Here, we construct a complete collection of defined mutants in protein-coding genes of this organism, identifying all genes that are essential under laboratory conditions. The collection, named NeMeSys 2.0, consists of individual mutants in 1584 non-essential genes. We identify 391 essential genes, which are associated with basic functions such as expression and preservation of genome information, cell membrane structure and function, and metabolism. We use this collection to shed light on the functions of diverse genes, including a gene encoding a member of a previously unrecognised class of histidinol-phosphatases; a set of 20 genes required for type IV pili function; and several conditionally essential genes encoding antitoxins and/or immunity proteins. We expect that NeMeSys 2.0 will facilitate the phenotypic profiling of a major human bacterial pathogen.

scholarly journals Markerless Mutagenesis in Methanococcus maripaludis Demonstrates Roles for Alanine Dehydrogenase, Alanine Racemase, and Alanine Permease

2005 ◽  
Vol 187 (3) ◽  
pp. 972-979 ◽  
Author(s):  
Brian C. Moore ◽  
John A. Leigh
Keyword(s):  
Negative Selection ◽  
Alanine Racemase ◽  
Selection Strategy ◽  
Methanococcus Maripaludis ◽  
Gene Encoding ◽  
Gram Positive Bacteria ◽  
Alanine Dehydrogenase ◽  
Genes Encoding ◽  
Base Analog ◽  
Type Gene

ABSTRACT Among the archaea, Methanococcus maripaludis has the unusual ability to use l- or d-alanine as a nitrogen source. To understand how this occurs, we tested the roles of three adjacent genes encoding homologs of alanine dehydrogenase, alanine racemase, and alanine permease. To produce mutations in these genes, we devised a method for markerless mutagenesis that builds on previously established genetic tools for M. maripaludis. The technique uses a negative selection strategy that takes advantage of the ability of the M. maripaludis hpt gene encoding hypoxanthine phosphoribosyltransferase to confer sensitivity to the base analog 8-azahypoxanthine. In addition, we developed a negative selection method to stably incorporate constructs into the genome at the site of the upt gene encoding uracil phosphoribosyltransferase. Mutants with in-frame deletion mutations in the genes for alanine dehydrogenase and alanine permease lost the ability to grow on either isomer of alanine, while a mutant with an in-frame deletion mutation in the gene for alanine racemase lost only the ability to grow on d-alanine. The wild-type gene for alanine dehydrogenase, incorporated into the upt site, complemented the alanine dehydrogenase mutation. Hence, the permease is required for the transport of either isomer, the dehydrogenase is specific for the l isomer, and the racemase converts the d isomer to the l isomer. Phylogenetic analysis indicated that all three genes had been acquired by lateral gene transfer from the low-moles-percent G+C gram-positive bacteria.

scholarly journals Urinary isolates of apramycin-resistantEscherichia coliandKlebsiella pneumoniaefrom Dublin

1995 ◽  
Vol 114 (1) ◽  
pp. 105-112 ◽  
Author(s):  
A. P. Johnson ◽  
M. Malde ◽  
N. Woodford ◽  
R. J. Cunney ◽  
E. G. Smyth
Keyword(s):  
Antimicrobial Agents ◽  
Dublin Hospital ◽  
Aminoglycoside Antibiotic ◽  
Restriction Enzyme Digestion ◽  
Hygromycin B ◽  
Gene Encoding ◽  
E Coli ◽  
Type Iv ◽  
Genes Encoding ◽  
Urinary Isolates

SUMMARYTwenty-two gentamicin-resistant urinary isolates ofEscherichia coliand five gentamicin-resistant urinary isolates ofKlebsiella pneumoniaefrom a Dublin hospital were examined for resistance to the veterinary aminoglycoside antibiotic apramycin. Five isolates ofE. coliand one isolate ofK. pneumoniaewere found to be resistant. The apramycin-resistant isolates, which were also resistant to the veterinary anthelmintic agent hygromycin B, hybridized with a DNA probe for the gene encoding the enzyme 3-N-aminoglycoside acetyltransferase type IV (AAC(3)IV). Resistance to apramycin and hygromycin B was co-transferable in four of the five isolates ofE. coliand the isolate ofK. pneumoniae.In one isolate ofE. coliapramycin resistance was not transferable. On the basis of their restriction enzyme digestion profiles and the antimicrobial resistance traits encoded, the transferable plasmids encoding resistance to apramycin and hygromycin B comprised three distinct types. Genetic linkage between the gene encoding AAC(3)IV and genes encoding resistance to ampicillin and either tetracycline or trimethoprim, means that the relatively widespread use of these antimicrobial agents provides a selective pressure for the persistence of resistance to apramycin and gentamicin even in the absence of bacterial exposure to aminoglycosides.

scholarly journals Expression and function of the cdgD gene, encoding a CHASE–PAS-DGC-EAL domain protein, in Azospirillum brasilense

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
José Francisco Cruz-Pérez ◽  
Roxana Lara-Oueilhe ◽  
Cynthia Marcos-Jiménez ◽  
Ricardo Cuatlayotl-Olarte ◽  
María Luisa Xiqui-Vázquez ◽  
...  
Keyword(s):  
Azospirillum Brasilense ◽  
Type Strain ◽  
Wild Type Strain ◽  
Soil Conditions ◽  
Wild Type ◽  
Gene Encoding ◽  
Wheat Roots ◽  
Genes Encoding ◽  
In The Wild ◽  
Plant Growth Promoting

AbstractThe plant growth-promoting bacterium Azospirillum brasilense contains several genes encoding proteins involved in the biosynthesis and degradation of the second messenger cyclic-di-GMP, which may control key bacterial functions, such as biofilm formation and motility. Here, we analysed the function and expression of the cdgD gene, encoding a multidomain protein that includes GGDEF-EAL domains and CHASE and PAS domains. An insertional cdgD gene mutant was constructed, and analysis of biofilm and extracellular polymeric substance production, as well as the motility phenotype indicated that cdgD encoded a functional diguanylate protein. These results were correlated with a reduced overall cellular concentration of cyclic-di-GMP in the mutant over 48 h compared with that observed in the wild-type strain, which was recovered in the complemented strain. In addition, cdgD gene expression was measured in cells growing under planktonic or biofilm conditions, and differential expression was observed when KNO3 or NH4Cl was added to the minimal medium as a nitrogen source. The transcriptional fusion of the cdgD promoter with the gene encoding the autofluorescent mCherry protein indicated that the cdgD gene was expressed both under abiotic conditions and in association with wheat roots. Reduced colonization of wheat roots was observed for the mutant compared with the wild-type strain grown in the same soil conditions. The Azospirillum-plant association begins with the motility of the bacterium towards the plant rhizosphere followed by the adsorption and adherence of these bacteria to plant roots. Therefore, it is important to study the genes that contribute to this initial interaction of the bacterium with its host plant.

Structure, expression, chromosomal location and product of the gene encoding Adh2 in Petunia.

Genetics ◽  
1993 ◽  
Vol 133 (4) ◽  
pp. 999-1007
Author(s):  
R G Gregerson ◽  
L Cameron ◽  
M McLean ◽  
P Dennis ◽  
J Strommer
Keyword(s):  
Chromosomal Location ◽  
Higher Plants ◽  
Gene Encoding ◽  
Genomic Libraries ◽  
Regulatory Strategy ◽  
Adh1 Gene ◽  
Adh Genes ◽  
Genes Encoding ◽  
Adh Gene ◽  
Polymerase Chain

Abstract In most higher plants the genes encoding alcohol dehydrogenase comprise a small gene family, usually with two members. The Adh1 gene of Petunia has been cloned and analyzed, but a second identifiable gene was not recovered from any of three genomic libraries. We have therefore employed the polymerase chain reaction to obtain the major portion of a second Adh gene. From sequence, mapping and northern data we conclude this gene encodes ADH2, the major anaerobically inducible Adh gene of Petunia. The availability of both Adh1 and Adh2 from Petunia has permitted us to compare their structures and patterns of expression to those of the well-studied Adh genes of maize, of which one is highly expressed developmentally, while both are induced in response to hypoxia. Despite their evolutionary distance, evidenced by deduced amino acid sequence as well as taxonomic classification, the pairs of genes are regulated in strikingly similar ways in maize and Petunia. Our findings suggest a significant biological basis for the regulatory strategy employed by these distant species for differential expression of multiple Adh genes.

scholarly journals Non-Syndromic Dentinogenesis Imperfecta Caused by Mild Mutations in COL1A2

2021 ◽  
Vol 11 (6) ◽  
pp. 526
Author(s):  
Yejin Lee ◽  
Youn Jung Kim ◽  
Hong-Keun Hyun ◽  
Jae-Cheoun Lee ◽  
Zang Hee Lee ◽  
...  
Keyword(s):  
Collagen Type ◽  
Molecular Genetic ◽  
Collagen Type I ◽  
Type I ◽  
Dentinogenesis Imperfecta ◽  
Gene Encoding ◽  
Korean Families ◽  
Whole Exome ◽  
Genes Encoding ◽  
Candidate Gene Sequencing

Hereditary dentin defects can be categorized as a syndromic form predominantly related to osteogenesis imperfecta (OI) or isolated forms without other non-oral phenotypes. Mutations in the gene encoding dentin sialophosphoprotein (DSPP) have been identified to cause dentinogenesis imperfecta (DGI) Types II and III and dentin dysplasia (DD) Type II. While DGI Type I is an OI-related syndromic phenotype caused mostly by monoallelic mutations in the genes encoding collagen type I alpha 1 chain (COL1A1) and collagen type I alpha 2 chain (COL1A2). In this study, we recruited families with non-syndromic dentin defects and performed candidate gene sequencing for DSPP exons and exon/intron boundaries. Three unrelated Korean families were further analyzed by whole-exome sequencing due to the lack of the DSPP mutation, and heterozygous COL1A2 mutations were identified: c.3233G>A, p.(Gly1078Asp) in Family 1 and c.1171G>A, p.(Gly391Ser) in Family 2 and 3. Haplotype analysis revealed different disease alleles in Families 2 and 3, suggesting a mutational hotspot. We suggest expanding the molecular genetic etiology to include COL1A2 for isolated dentin defects in addition to DSPP.

scholarly journals The G-Protein α-Subunit GasC Plays a Major Role in Germination in the Dimorphic FungusPenicillium marneffei

Genetics ◽  
2003 ◽  
Vol 164 (2) ◽  
pp. 487-499 ◽  
Author(s):  
Sophie Zuber ◽  
Michael J Hynes ◽  
Alex Andrianopoulos
Keyword(s):  
G Protein ◽  
Germination Rate ◽  
Yeast Cells ◽  
Class Iii ◽  
Temperature Dependent ◽  
Gene Encoding ◽  
Α Subunit ◽  
G Protein Α Subunit ◽  
Opportunistic Human Pathogen

AbstractThe opportunistic human pathogen Penicillium marneffei exhibits a temperature-dependent dimorphic switch. At 25°, multinucleate, septate hyphae that can undergo differentiation to produce asexual spores (conidia) are produced. At 37° hyphae undergo arthroconidiation to produce uninucleate yeast cells that divide by fission. This work describes the cloning of the P. marneffei gasC gene encoding a G-protein α-subunit that shows high homology to members of the class III fungal Gα-subunits. Characterization of a ΔgasC mutant and strains carrying a dominant-activating gasCG45R or a dominant-interfering gasCG207R allele show that GasC is a crucial regulator of germination. A ΔgasC mutant is severely delayed in germination, whereas strains carrying a dominant-activating gasCG45R allele show a significantly accelerated germination rate. Additionally, GasC signaling positively affects the production of the red pigment by P. marneffei at 25° and negatively affects the onset of conidiation and the conidial yield, showing that GasC function overlaps with functions of the previously described Gα-subunit GasA. In contrast to the S. cerevisiae ortholog Gpa2, our data indicate that GasC is not involved in carbon or nitrogen source sensing and plays no major role in either hyphal or yeast growth or in the switch between these two forms.

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