Analysis of mutations in the creA gene involved in carbon catabolite repression in Aspergillus nidulans

1996 ◽  
Vol 42 (9) ◽  
pp. 950-959 ◽  
Author(s):  
Robert A. Shroff ◽  
Robin A. Lockington ◽  
Joan M. Kelly
Keyword(s):  
Zinc Finger ◽  
Catabolite Repression ◽  
Carbon Catabolite Repression ◽  
Zinc Finger Protein ◽  
The Other ◽  
Transcriptional Analysis ◽  
Missense Mutations ◽  
Rapid Amplification ◽  
Translational Start ◽  
Carboxy Terminal

The molecular nature of a number of creA mutant alleles has been determined. Three alleles analysed are missense mutations in the DNA binding domain and predicted to reduce but not abolish binding. Of the other four alleles, two result from frameshifts: one has a nonsense mutation and the other has an inversion. All four alleles result in truncations of the protein after the zinc finger domain, such that the protein no longer contains at least the carboxy terminal 145 amino acids, so identifying a region required for repression. Transcriptional analysis of creA indicates that the transcript is autoregulated and analysis using 5′ rapid amplification of cDNA ends indicates that transcriptional start points exist in clusters over a region of 200 bp located up to 595 bp 5′ of the translational start point. The two major clusters have potential CREA-binding sites (SYGGRG) at appropriate positions to allow autoregulation. Autoregulation leads to the creA transcript being most abundant in carbon catabolite nonrepressing conditions, and this, together with the phenotypes of the mutant alleles, has led to the suggestion that CREA has effects under conditions generally not considered as carbon catabolite repressing, as well as in carbon catabolite repressing conditions.Key words: carbon catabolite repression, MIG1, CREA, zinc finger protein, transcriptional repressor.

scholarly journals Effect of Glucose on Endo-xylanase and β-xylosidase Production by Fungi Isolated in Indonesia

2022 ◽  
Author(s):  
Ririn Krisnawati ◽  
Sardjono ◽  
Jaka Widada ◽  
Dian Anggraini Suroto ◽  
Muhammad Nur Cahyanto
Keyword(s):  
Liquid Medium ◽  
Growth Medium ◽  
Catabolite Repression ◽  
Carbon Catabolite Repression ◽  
The Other ◽  
Trichoderma Asperellum ◽  
Aspergillus Aculeatus ◽  
Xylanase Production ◽  
Degrading Enzymes ◽  
Effect Of Glucose

Xylanases are widely produced by fungi, and the production of polysaccharide-degrading enzymes, in general, are usually subjected to carbon catabolite repression. In this work, the ability of several Indonesian indigenous fungi to produce endo-xylanase and β-xylosidase and their responses to glucose as a repressor were determined. Ten fungi were grown in a liquid medium supplemented with glucose as the repressor (0, 1%, 3%, and 5%), and the endo-xylanase and β-xylosidase productions were assayed. Aspergillus aculeatus FIG1 and A. oryzae KKB4 produced 3.85 and 0.70 U/mL of endo-xylanase, respectively, compared with other strains (0.22 U/mL or less). Trichoderma asperellum PK1J2, T. virens MLT2J2, A. aculeatus FIG1, T. asperellum MLT5J1, A. oryzae KKB4, and T. asperellum MLT3J2 produced 0.021–0.065 U/mL of β-xylosidase, whereas the other strains produced 0.013 U/mL or less of β-xylosidase. Adding 1% glucose to the growth medium can partially repress endo-xylanase production in A. aculeatus FIG1, T. asperellum PK1J2, and T. virens MLT4J1 and completely repress other strains. By adding 1% glucose, strains FIG1, PK1J2, and MLT4J1 suffered almost complete repression of β-xylosidase production, although such strains exhibited partial repression of endo-xylanase production. β-Xylosidase produced by the other strains showed complete repression by adding 1% glucose, except for A. aculeatus FIG1, A. tamarii FNCC 6151, and T. asperellum MLT1J1, which showed partial repression. Therefore, adding 3% glucose to the growth medium can result in complete repression of endo-xylanase and β-xylosidase productions in all strains examined.

scholarly journals CcpA Mediates Proline Auxotrophy and Is Required for Staphylococcus aureus Pathogenesis

2010 ◽  
Vol 192 (15) ◽  
pp. 3883-3892 ◽  
Author(s):  
Chunling Li ◽  
Fei Sun ◽  
Hoonsik Cho ◽  
Vamshi Yelavarthi ◽  
Changmo Sohn ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Catabolite Repression ◽  
Carbon Catabolite Repression ◽  
Selective Pressure ◽  
Missense Mutations ◽  
Ornithine Aminotransferase ◽  
Gram Positive Bacteria ◽  
The Third ◽  
Transposon Insertion ◽  
Ornithine Cyclodeaminase

ABSTRACT Human clinical isolates of Staphylococcus aureus, for example, strains Newman and N315, cannot grow in the absence of proline, albeit their sequenced genomes harbor genes for two redundant proline synthesis pathways. We show here that under selective pressure, S. aureus Newman generates proline-prototrophic variants at a frequency of 3 × 10−6, introducing frameshift and missense mutations in ccpA or IS1811 insertions in ptsH, two regulatory genes that carry out carbon catabolite repression (CCR) in staphylococci and other Gram-positive bacteria. S. aureus Newman variants with mutations in rocF (arginase), rocD (ornithine aminotransferase), and proC (Δ1-pyrroline 5-carboxylate [P5C] reductase) are unable to generate proline-prototrophic variants, whereas a variant with a mutation in ocd (ornithine cyclodeaminase) is unaffected. Transposon insertion in ccpA also restored proline prototrophy. CcpA was shown to repress transcription of rocF and rocD, encoding the first two enzymes, but not of proC, encoding the third and final enzyme in the P5C reductase pathway. CcpA bound to the upstream regions of rocF and rocD but not to that of proC. CcpA's binding to the upstream regions was greatly enhanced by phosphorylated HPr. The CCR-mediated proline auxotrophy was lifted when nonpreferred carbohydrates were used as the sole carbon source. The ccpA mutant displayed reduced staphylococcal load and replication in a murine model of staphylococcal abscess formation, indicating that carbon catabolite repression presents an important pathogenesis strategy of S. aureus infections.

Opl: a zinc finger protein that regulates neural determination and patterning in Xenopus

Development ◽  
1998 ◽  
Vol 125 (15) ◽  
pp. 2867-2882 ◽  
Author(s):  
J.S. Kuo ◽  
M. Patel ◽  
J. Gamse ◽  
C. Merzdorf ◽  
X. Liu ◽  
...  
Keyword(s):  
Neural Crest ◽  
Zinc Finger ◽  
Neural Tube ◽  
Zinc Finger Protein ◽  
Neural Patterning ◽  
Dorsal Neural Tube ◽  
Finger Protein ◽  
Pair Rule Gene ◽  
Carboxy Terminal ◽  
Pair Rule

In order to study the mechanism of neural patterning in Xenopus, we used subtractive cloning to isolate genes activated early during this process. One gene isolated was opl, (odd-paired-like) that resembles the Drosophila pair-rule gene odd-paired and encodes a zinc finger protein that is a member of the Zic gene family. At the onset of gastrulation, opl is expressed throughout the presumptive neural plate, indicating that neural determination has begun at this stage while, by neurula, opl expression is restricted to the dorsal neural tube and neural crest. opl encodes a transcriptional activator, with a carboxy terminal regulatory domain, which when removed increases opl activity. opl both sensitizes animal cap ectoderm to the neural inducer noggin and alters the spectrum of genes induced by noggin, allowing activation of the midbrain marker engrailed. Consistent with the later dorsal neural expression of opl, the activated form of opl is able to induce neural crest and dorsal neural tube markers both in animal caps and whole embryos. In ventral ectoderm, opl induces formation of loose cell aggregates that may indicate neural crest precursor cells. Aggregates do not express an epidermal marker, indicating that opl suppresses ventral fates. Together, these data suggest that opl may mediate neural competence and may be involved in activation of midbrain, dorsal neural and neural crest fates.

scholarly journals Multiple Alternate Transcripts Direct the Biosynthesis of Microcystin, a Cyanobacterial

2002 ◽  
Vol 68 (2) ◽  
pp. 449-455 ◽  
Author(s):  
Melanie Kaebernick ◽  
Elke Dittmann ◽  
Thomas B�rner ◽  
Brett A. Neilan
Keyword(s):  
Gene Cluster ◽  
Polyketide Synthase ◽  
Bidirectional Promoter ◽  
Transcriptional Analysis ◽  
Transcription Start ◽  
Transcription Start Sites ◽  
Reverse Transcription Pcr ◽  
Peptide Synthetase ◽  
Rapid Amplification ◽  
Translational Start

ABSTRACT The mcyABCDEFGHIJ gene cluster of Microcystis aeruginosa encodes the mixed polyketide synthase/nonribosomal peptide synthetase (microcystin synthetase) which is responsible for biosynthesis of the potent liver toxin microcystin. The sequence and orientation of the mcy genes have previously been reported, but no transcriptional analysis had been performed prior to this study. The mcyABCDEFGHIJ genes are transcribed as two polycistronic operons, mcyABC and mcyDEFGHIJ, from a central bidirectional promoter between mcyA and mcyD. Two transcription start sites were detected for both mcyA and mcyD when cells were exposed to light intensities of 68 and 16 μmol of photons m−2 s−1. The start sites, located 206 and 254 bp upstream of the translational start for mcyD under high and low light conditions, respectively, indicate long untranslated leader regions. Putative transcription start sites were also identified for mcyE, mcyF, mcyG, mcyH, mcyI, and mcyJ but not for mcyB and mcyC. A combination of reverse transcription-PCR and rapid amplification of cDNA ends was employed throughout this work, which may have been one of the first transcriptional analyses of a large nonribosomal polyketide gene cluster.

scholarly journals BZP, a novel serum-responsive zinc finger protein that inhibits gene transcription.

1994 ◽  
Vol 14 (10) ◽  
pp. 6773-6788 ◽  
Author(s):  
A J Franklin ◽  
T L Jetton ◽  
K D Shelton ◽  
M A Magnuson
Keyword(s):  
Zinc Finger ◽  
Zinc Finger Protein ◽  
Subcellular Location ◽  
Inhibitory Effect ◽  
Amino Acid Identity ◽  
Cdna Clones ◽  
Mouse Tissues ◽  
Hit Cells ◽  
Simplex Virus ◽  
Carboxy Terminal

We report the fortuitous isolation of cDNA clones encoding a novel zinc finger DNA-binding protein termed BZP. The protein encoded is 114 kDa and contains eight zinc finger motifs, seven of which are present in two clusters at opposite ends of the molecule. Both finger clusters bound to the 9-bp sequence AAAGGTGCA with apparent Kds of approximately 2.5 nM. Two of the finger motifs within the amino- and carboxy-terminal finger clusters share 63% amino acid identity. BZP inhibited transcription of the herpes simplex virus thymidine kinase promoter when copies of the 9-bp target motif were linked in cis, suggesting that it functions as a transcriptional repressor. BZP mRNA and immunoreactivity were detected in several established cell lines but were most abundant in hamster insulinoma (HIT) cells, the parental source of the cDNAs. In mouse tissues, BZP mRNA and immunoreactivity were identified in cells of the endocrine pancreas, anterior pituitary, and central nervous system. Interestingly, in HIT cells proliferating in culture, BZP immunoreactivity was predominately nuclear in location, whereas it was usually located in the cytoplasm in most neural and neuroendocrine tissues. Serum deprivation of HIT cells caused BZP immunoreactivity to become predominantly cytoplasmic in location and attenuated its inhibitory effect on transcription, thereby suggesting that the both the subcellular location and the function of this protein are modulated by factors in serum.

BZP, a novel serum-responsive zinc finger protein that inhibits gene transcription

1994 ◽  
Vol 14 (10) ◽  
pp. 6773-6788
Author(s):  
A J Franklin ◽  
T L Jetton ◽  
K D Shelton ◽  
M A Magnuson
Keyword(s):  
Zinc Finger ◽  
Zinc Finger Protein ◽  
Subcellular Location ◽  
Inhibitory Effect ◽  
Amino Acid Identity ◽  
Cdna Clones ◽  
Mouse Tissues ◽  
Hit Cells ◽  
Simplex Virus ◽  
Carboxy Terminal

We report the fortuitous isolation of cDNA clones encoding a novel zinc finger DNA-binding protein termed BZP. The protein encoded is 114 kDa and contains eight zinc finger motifs, seven of which are present in two clusters at opposite ends of the molecule. Both finger clusters bound to the 9-bp sequence AAAGGTGCA with apparent Kds of approximately 2.5 nM. Two of the finger motifs within the amino- and carboxy-terminal finger clusters share 63% amino acid identity. BZP inhibited transcription of the herpes simplex virus thymidine kinase promoter when copies of the 9-bp target motif were linked in cis, suggesting that it functions as a transcriptional repressor. BZP mRNA and immunoreactivity were detected in several established cell lines but were most abundant in hamster insulinoma (HIT) cells, the parental source of the cDNAs. In mouse tissues, BZP mRNA and immunoreactivity were identified in cells of the endocrine pancreas, anterior pituitary, and central nervous system. Interestingly, in HIT cells proliferating in culture, BZP immunoreactivity was predominately nuclear in location, whereas it was usually located in the cytoplasm in most neural and neuroendocrine tissues. Serum deprivation of HIT cells caused BZP immunoreactivity to become predominantly cytoplasmic in location and attenuated its inhibitory effect on transcription, thereby suggesting that the both the subcellular location and the function of this protein are modulated by factors in serum.

Analysis of the creA gene, a regulator of carbon catabolite repression in Aspergillus nidulans

1991 ◽  
Vol 11 (11) ◽  
pp. 5701-5709 ◽  
Author(s):  
C E Dowzer ◽  
J M Kelly
Keyword(s):  
Aspergillus Nidulans ◽  
Zinc Finger ◽  
Catabolite Repression ◽  
Carbon Catabolite Repression ◽  
Wilms Tumor ◽  
Yeast Cells ◽  
Cdna Clones ◽  
Crea Gene ◽  
Zinc Finger Region

The complete nucleotide sequence derived from a genomic clone and two cDNA clones of the creA gene of Aspergillus nidulans is presented. The gene contains no introns. The derived polypeptide of 415 amino acids contains two zinc fingers of the C2H2 class, frequent S(T)PXX motifs, and an alanine-rich region indicative of a DNA-binding repressor protein. The amino acid sequence of the zinc finger region has 84% similarity to the zinc finger region of Mig1, a protein involved in carbon catabolite repression in yeast cells, and it is related both to the mammalian Egr1 and Egr2 proteins and to the Wilms' tumor protein. A deletion removing the creA gene was obtained, by using in vitro techniques, in both a heterokaryon and a diploid strain but was unobtainable in a pure haploid condition. Evidence is presented suggesting that the phenotype of such a deletion, when not complemented by another creA allele, is leaky lethality allowing limited germination of the spore but not colony formation. This phenotype is far more extreme than that of any of the in vivo-generated mutations, and thus either the gene product may have an activator activity as well as a repressor function or some residual repressor function may be required for full viability.

scholarly journals Catabolite repression of phosphoenolpyruvate carboxykinase by a zinc finger protein under biotin- and pyruvate carboxylase-deficient conditions in Pichia pastoris

Microbiology ◽  
2011 ◽  
Vol 157 (12) ◽  
pp. 3361-3369 ◽  
Author(s):  
Nallani Vijay Kumar ◽  
Pundi N. Rangarajan
Keyword(s):  
Pichia Pastoris ◽  
Zinc Finger ◽  
Catabolite Repression ◽  
Pyruvate Carboxylase ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Zinc Finger Protein ◽  
Methylotrophic Yeast ◽  
Yeast Cells ◽  
Northern Analysis ◽  
Finger Protein

We have identified a methanol- and biotin-starvation-inducible zinc finger protein named ROP [repressor of phosphoenolpyruvate carboxykinase (PEPCK)] in the methylotrophic yeast Pichia pastoris. When P. pastoris strain GS115 (wild-type, WT) is cultured in biotin-deficient, glucose-ammonium (Bio−) medium, growth is suppressed due to the inhibition of anaplerotic synthesis of oxaloacetate, catalysed by the biotin-dependent enzyme pyruvate carboxylase (PC). Deletion of ROP results in a strain (ΔROP) that can grow under biotin-deficient conditions due to derepression of a biotin- and PC-independent pathway of anaplerotic synthesis of oxaloacetate. Northern analysis as well as microarray expression profiling of RNA isolated from WT and ΔROP strains cultured in Bio− medium indicate that expression of the phosphoenolpyruvate carboxykinase gene (PEPCK) is induced in ΔROP during biotin- or PC-deficiency even under glucose-abundant conditions. There is an excellent correlation between PEPCK expression and growth of ΔROP in Bio− medium, suggesting that ROP-mediated regulation of PEPCK may have a crucial role in the biotin- and PC-independent growth of the ΔROP strain. To our knowledge, ROP is the first example of a zinc finger transcription factor involved in the catabolite repression of PEPCK in yeast cells cultured under biotin- or PC-deficient and glucose-abundant conditions.

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