scholarly journals Co-expression of the Mating-Type Genes Involved in Internuclear Recognition Is Lethal in Podospora anserina

Genetics ◽  
2000 ◽  
Vol 155 (2) ◽  
pp. 657-669 ◽  
Author(s):  
Evelyne Coppin ◽  
Robert Debuchy
Keyword(s):  
Mating Type ◽  
Transcriptional Control ◽  
Wild Type Strain ◽  
Podospora Anserina ◽  
Wild Type ◽  
Initial Development ◽  
Genes Encoding ◽  
In The Wild ◽  
Mating Type Genes ◽  
Mat Genes

Abstract In the heterothallic filamentous fungus Podospora anserina, four mating-type genes encoding transcriptional factors have been characterized: FPR1 in the mat+ sequence and FMR1, SMR1, and SMR2 in the alternative mat− sequence. Fertilization is controlled by FPR1 and FMR1. After fertilization, male and female nuclei, which have divided in the same cell, form mat+/mat− pairs during migration into the ascogenous hyphae. Previous data indicate that the formation of mat+/mat− pairs is controlled by FPR1, FMR1, and SMR2. SMR1 was postulated to be necessary for initial development of ascogenous hyphae. In this study, we investigated the transcriptional control of the mat genes by seeking mat transcripts during the vegetative and sexual phase and fusing their promoter to a reporter gene. The data indicate that FMR1 and FPR1 are expressed in both mycelia and perithecia, whereas SMR1 and SMR2 are transcribed in perithecia. Increased or induced vegetative expression of the four mat genes has no effect when the recombined gene is solely in the wild-type strain. However, the combination of resident FPR1 with deregulated SMR2 and overexpressed FMR1 in the same nucleus is lethal. This lethality is suppressed by the expression of SMR1, confirming that SMR1 operates downstream of the other mat genes.

scholarly journals Mutations in Mating-Type Genes of the Heterothallic Fungus Podospora anserina Lead to Self-Fertility

Genetics ◽  
2001 ◽  
Vol 159 (2) ◽  
pp. 545-556
Author(s):  
Sylvie Arnaise ◽  
Denise Zickler ◽  
Suzanne Le Bilcot ◽  
Corinne Poisier ◽  
Robert Debuchy
Keyword(s):  
Mating Type ◽  
Type Strain ◽  
Wild Type Strain ◽  
Male Partner ◽  
Podospora Anserina ◽  
Wild Type ◽  
Opposite Mating Type ◽  
Initial Development ◽  
Mating Type Genes ◽  
Further Development

Abstract The heterothallic fungus Podospora anserina has two mating-type alleles termed mat+ and mat−. The mat+ sequence contains one gene, FPR1, while mat− contains three genes: FMR1, SMR1, and SMR2. FPR1 and FMR1 are required for fertilization, which is followed by mitotic divisions of the two parental nuclei inside the female organ. This leads to the formation of plurinucleate cells containing a mixture of parental mat+ and mat− nuclei. Further development requires a recognition between mat+ and mat− nuclei before migration of the mat+/mat− pairs into specialized hyphae in which karyogamy, meiosis, and ascospore formation take place. FPR1, FMR1, and SMR2 control this internuclear recognition step. Initial development of the dikaryotic stage is supposed to require SMR1; disruption of SMR1 results in barren perithecia. In a systematic search for suppressors restoring fertility, we isolated 15 suppressors—all of them mutations in the mating-type genes. These fmr1, smr2, and fpr1 mutants, as well as the strains disrupted for FMR1, SMR2, and FPR1, are weakly self-fertile. They are able to act as the male partner on a strain of the same mating type and give a mixture of biparental and uniparental progeny when crossed with a wild-type strain of opposite mating type. These observations lead us to propose that SMR2, FMR1, and FPR1 act as activators and repressors of fertilization and internuclear recognition functions.

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.

scholarly journals Insights into an alternative pathway for glycerol metabolism in a glycerol kinase deficientPseudomonas putidaKT2440

2019 ◽  
Author(s):  
Meg Walsh ◽  
William Casey ◽  
Shane T. Kenny ◽  
Tanja Narancic ◽  
Lars M. Blank ◽  
...  
Keyword(s):  
Mutant Strain ◽  
Type Strain ◽  
Wild Type Strain ◽  
Alternative Pathway ◽  
Glycerol Kinase ◽  
Glycerol Metabolism ◽  
Wild Type ◽  
Short Chain Length ◽  
Genes Encoding ◽  
In The Wild

AbstractPseudomonas putidaKT2440 is known to metabolise glycerol via glycerol-3-phosphate using glycerol kinase an enzyme previously described as critical for glycerol metabolism (1). However, when glycerol kinase was knocked out inP. putidaKT2440 it retained the ability to use glycerol as the sole carbon source, albeit with a much-extended lag period and 2 fold lower final biomass compared to the wild type strain. A metabolomic study identified glycerate as a major and the most abundant intermediate in glycerol metabolism in this mutated strain with levels 21-fold higher than wild type. Erythrose-4-phosphate was detected in the mutant strain, but not in the wild type strain. Glyceraldehyde and glycraldehyde-3-phosphate were detected at similar levels in the mutant strain and the wild type. Transcriptomic studies identified 191 genes that were more than 2-fold upregulated in the mutant compared to the wild type and 175 that were down regulated. The genes involved in short chain length fatty acid metabolism were highly upregulated in the mutant strain. The genes encoding 3-hydroxybutyrate dehydrogenase were 5.8-fold upregulated and thus the gene was cloned, expressed and purified to reveal it can act on glyceraldehyde but not glycerol as a substrate.

scholarly journals Transcriptional Control by A-Factor of Two Trypsin Genes in Streptomyces griseus

2005 ◽  
Vol 187 (1) ◽  
pp. 286-295 ◽  
Author(s):  
Jun-ya Kato ◽  
Won-Jae Chi ◽  
Yasuo Ohnishi ◽  
Soon-Kwang Hong ◽  
Sueharu Horinouchi
Keyword(s):  
Type Strain ◽  
Transcriptional Control ◽  
Time Course ◽  
Wild Type Strain ◽  
Streptomyces Griseus ◽  
Trypsin Activity ◽  
Wild Type ◽  
Regulatory Cascade ◽  
Transcriptional Start Point ◽  
In The Wild

ABSTRACT AdpA is the key transcriptional activator for a number of genes of various functions in the A-factor regulatory cascade in Streptomyces griseus, forming an AdpA regulon. Trypsin-like activity was detected at a late stage of growth in the wild-type strain but not in an A-factor-deficient mutant. Consistent with these observations, two trypsin genes, sprT and sprU, in S. griseus were found to be members of the AdpA regulon; AdpA activated the transcription of both genes by binding to the operators located at about −50 nucleotide positions with respect to the transcriptional start point. The transcription of sprT and sprU, induced by AdpA, was most active at the onset of sporulation. Most trypsin activity exerted by S. griseus was attributed to SprT, because trypsin activity in an sprT-disrupted mutant was greatly reduced but that in an sprU-disrupted mutant was only slightly reduced. This was consistent with the observation that the amount of the sprT mRNA was much greater than that of the sprU transcript. Disruption of both sprT and sprU (mutant ΔsprTU) reduced trypsin activity to almost zero, indicating that no trypsin genes other than these two were present in S. griseus. Even the double mutant ΔsprTU grew normally and developed aerial hyphae and spores over the same time course as the wild-type strain.

scholarly journals Altered mating-type identity in the fungus Podospora anserina leads to selfish nuclei, uniparental progeny, and haploid meiosis.

Genetics ◽  
1995 ◽  
Vol 140 (2) ◽  
pp. 493-503 ◽  
Author(s):  
D Zickler ◽  
S Arnaise ◽  
E Coppin ◽  
R Debuchy ◽  
M Picard
Keyword(s):  
Mating Type ◽  
Podospora Anserina ◽  
Wild Type ◽  
Selfish Behavior ◽  
Developmental Patterns ◽  
Filamentous Ascomycete ◽  
Type Identity ◽  
Mat Locus ◽  
Mat Genes

Abstract In wild-type crosses of the filamentous ascomycete Podospora anserina, after fertilization, only nuclei of opposite mating type can form dikaryons that undergo karyogamy and meiosis, producing biparental progeny. To determine the role played by the mating type in these steps, the four mat genes were mutagenized in vitro and introduced into a strain deleted for its mat locus. Genetic and cytological analyses of these mutant strain, crossed to each other and to wild type, showed that mating-type information is required for recognition of nuclear identity during the early steps of sexual reproduction. In crosses with strain carrying a mating-type mutation, two unusual developmental patterns were observed: monokaryotic cells, resulting in haploid meiosis, and uniparental dikaryotic cells providing, after karyogamy and meiosis, a uniparental progeny. Altered mating-type identity leads to selfish behavior of the mutant nucleus: it migrates alone or paired, ignoring its wild-type partner in all mutant x wild-type crosses. This behavior is nucleus-autonomous because, in the same cytoplasm, the wild-type nuclei form only biparental dikaryons. In P. anserina, mat genes are thus required to ensure a biparental dikaryotic state but appear dispensable for later stages, such as meiosis and sporulation.

scholarly journals Oxygen Regulation of the ccoN Gene Encoding a Component of the cbb3 Oxidase inRhodobacter sphaeroides 2.4.1T: Involvement of the FnrL Protein

1998 ◽  
Vol 180 (8) ◽  
pp. 2228-2231 ◽  
Author(s):  
Nigel J. Mouncey ◽  
Samuel Kaplan
Keyword(s):  
Rhodobacter Sphaeroides ◽  
Type Strain ◽  
Wild Type Strain ◽  
Growth Conditions ◽  
Anaerobic Growth ◽  
Wild Type ◽  
Transcriptional Fusion ◽  
Gene Encoding ◽  
Genes Encoding ◽  
In The Wild

ABSTRACT The ccoNOQP gene cluster of Rhodobacter sphaeroides 2.4.1T encodes acbb 3 cytochrome oxidase which is utilized in oxygen-limited conditions for aerobic respiration. The β-galactosidase activity of accoN::lacZ transcriptional fusion was low under high (30%)-oxygen and anaerobic growth conditions. Maximal ccoN::lacZexpression was observed when the oxygen concentration was lowered to 2%. In an FnrL mutant,ccoN::lacZ expression was significantly lower than in the wild-type strain, suggesting that FnrL is a positive regulator of genes encoding thecbb 3 oxidase.

scholarly journals Effects of Mutations of RAD50, RAD51, RAD52, and Related Genes on Illegitimate Recombination in Saccharomyces cerevisiae

Genetics ◽  
1996 ◽  
Vol 142 (2) ◽  
pp. 383-391 ◽  
Author(s):  
Yasumasa Tsukamoto ◽  
Jun-ichi Kato ◽  
Hideo Ikeda
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Quantitative Analysis ◽  
Structural Analysis ◽  
Recombination Rate ◽  
Type Strain ◽  
Negative Selection ◽  
Wild Type Strain ◽  
Illegitimate Recombination ◽  
Wild Type ◽  
In The Wild

Abstract To examine the mechanism of illegitimate recombination in Saccharomyces cerevisiae, we have developed a plasmid system for quantitative analysis of deletion formation. A can1 cyh2 cell carrying two negative selection markers, the CAN1 and CYH2 genes, on a YCp plasmid is sensitive to canavanine and cycloheximide, but the cell becomes resistant to both drugs when the plasmid has a deletion over the CAN1 and CYH2 genes. Structural analysis of the recombinant plasmids obtained from the resistant cells showed that the plasmids had deletions at various sites of the CAN1-CYH2 region and there were only short regions of homology (1-5 bp) at the recombination junctions. The results indicated that the deletion detected in this system were formed by illegitimate recombination. Study on the effect of several rad mutations showed that the recombination rate was reduced by 30-, 10-, 10-, and 10-fold in the rad52, rad50, mre11, and xrs2 mutants, respectively, while in the rud51, 54, 55, and 57 mutants, the rate was comparable to that in the wild-type strain. The rad52 mutation did not affect length of homology at junction sites of illegitimate recombination.

scholarly journals Cloning and characterization of four SIR genes of Saccharomyces cerevisiae.

1986 ◽  
Vol 6 (2) ◽  
pp. 688-702 ◽  
Author(s):  
J M Ivy ◽  
A J Klar ◽  
J B Hicks
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mating Type ◽  
Blot Analysis ◽  
Transcriptional Control ◽  
Genomic Library ◽  
Yeast Saccharomyces Cerevisiae ◽  
Mating Type Genes ◽  
Rna Blots

Mating type in the yeast Saccharomyces cerevisiae is determined by the MAT (a or alpha) locus. HML and HMR, which usually contain copies of alpha and a mating type information, respectively, serve as donors in mating type interconversion and are under negative transcriptional control. Four trans-acting SIR (silent information regulator) loci are required for repression of transcription. A defect in any SIR gene results in expression of both HML and HMR. The four SIR genes were isolated from a genomic library by complementation of sir mutations in vivo. DNA blot analysis suggests that the four SIR genes share no sequence homology. RNA blots indicate that SIR2, SIR3, and SIR4 each encode one transcript and that SIR1 encodes two transcripts. Null mutations, made by replacement of the normal genomic allele with deletion-insertion mutations created in the cloned SIR genes, have a Sir- phenotype and are viable. Using the cloned genes, we showed that SIR3 at a high copy number is able to suppress mutations of SIR4. RNA blot analysis suggests that this suppression is not due to transcriptional regulation of SIR3 by SIR4; nor does any SIR4 gene transcriptionally regulate another SIR gene. Interestingly, a truncated SIR4 gene disrupts regulation of the silent mating type loci. We propose that interaction of at least the SIR3 and SIR4 gene products is involved in regulation of the silent mating type genes.

Characterization of Enterococcus faecium mutants resistant to mundticin KS, a class IIa bacteriocin

Microbiology ◽  
2003 ◽  
Vol 149 (10) ◽  
pp. 2901-2908 ◽  
Author(s):  
Youko Sakayori ◽  
Mizuho Muramatsu ◽  
Satoshi Hanada ◽  
Yoichi Kamagata ◽  
Shinichi Kawamoto ◽  
...  
Keyword(s):  
Enterococcus Faecium ◽  
Antimicrobial Agents ◽  
Wild Type Strain ◽  
Unsaturated Fatty Acids ◽  
Class I ◽  
Wild Type ◽  
Food Preservatives ◽  
In The Wild ◽  
Resistant Mutants

The emergence and spread of mutants resistant to bacteriocins would threaten the safety of using bacteriocins as food preservatives. To determine the physiological characteristics of resistant mutants, mutants of Enterococcus faecium resistant to mundticin KS, a class IIa bacteriocin, were isolated. Two types of mutant were found that had different sensitivities to other antimicrobial agents such as nisin (class I) and kanamycin. Both mutants were resistant to mundticin KS even in the absence of Mg2+ ions. The composition of unsaturated fatty acids in the resistant mutants was significantly increased in the presence of mundticin KS. The composition of the phospholipids in the two resistant mutants also differed from those in the wild-type strain. The putative zwitterionic amino-containing phospholipid in both mutants significantly increased, whereas amounts of phosphatidylglycerol and cardiolipin decreased. These changes in membrane structure may influence resistance of enterococci to class IIa and class I bacteriocins.

scholarly journals The sum1-1 mutation affects silent mating-type gene transcription in Saccharomyces cerevisiae.

1990 ◽  
Vol 10 (1) ◽  
pp. 409-412 ◽  
Author(s):  
G P Livi ◽  
J B Hicks ◽  
A J Klar
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mating Type ◽  
Transcriptional Control ◽  
Gene Mutations ◽  
State Level ◽  
Mating Type Gene ◽  
Gene Transcripts ◽  
Mating Type Genes ◽  
Type Gene ◽  
Type Information

The silent mating-type genes (HML and HMR) of Saccharomyces cerevisiae are kept under negative transcriptional control by the trans-acting products of the four MAR/SIR loci. MAR/SIR gene mutations result in the simultaneous derepression of HML and HMR gene expression. The sum1-1 mutation was previously identified as an extragenic suppressor of mutations in MAR1 (SIR2) and MAR2 (SIR3). As assayed genetically, sum1-1 is capable of restoring repression of silent mating-type information in cells containing mar1 or mar2 null mutations. We show here that the mating-type phenotype associated with sum1-1 results from a dramatic reduction in the steady-state level of HML and HMR gene transcripts. At the same time, the sum1-1 mutation has no significant effect on the level of each of the four MAR/SIR mRNAs.

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