scholarly journals Developmentally regulated enzymes and cyclic AMP-binding sites in Dictyostelium discoideum cells blocked during development by α-chymotrypsin

1982 ◽  
Vol 206 (2) ◽  
pp. 185-193
Author(s):  
J A Schmidt ◽  
J L Stirling
Keyword(s):  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Binding Sites ◽  
Glycogen Phosphorylase ◽  
Specific Activity ◽  
Tyrosine Aminotransferase ◽  
Carbohydrate Binding ◽  
Threonine Deaminase ◽  
Developmentally Regulated ◽  
Beta Glucosidase

When cells of the slime mould Dictyostelium discoideum are allowed to starve in the presence of alpha-chymotrypsin, they are blocked in development at the stage where tight aggregates form tips. Analysis of developmentally regulated enzymes has shown that alpha-mannosidase, beta-N-acetylglucosaminidase, threonine deaminase, tyrosine aminotransferase, beta-glucosidase and the carbohydrate-binding protein discoidin are unaffected, but enzymes that show an increase in specific activity during post-aggregative development, namely glycogen phosphorylase, UDP-glucose pyrophosphorylase, UDP-galactose 4-epimerase, UDP-galactose polysaccharide transferase and alkaline phosphatase, did not show the characteristic increase when development was blocked by alpha-chymotrypsin. Recovery of cells from the effects of alpha-chymotrypsin was accompanied by the formation of fruiting bodies and a concomitant increase in the specific activity of UDP-glucose pyrophosphorylase. Uptake or efflux of 45Ca2+ was not altered in the presence of alpha-chymotrypsin. Cells allowed to develop in alpha-chymotrypsin, or treated with the enzyme for 15 min, had a markedly reduced ability to bind cyclic AMP with low affinity; high-affinity binding was unaffected. Pronase had a similar effect on cyclic AMP binding, but trypsin, which does not alter developmental processes, has no effect on cyclic AMP binding to D. discoideum cells.

Two divergently transcribed genes of Dictyostelium discoideum are cyclic AMP-inducible and coregulated during development

1987 ◽  
Vol 7 (12) ◽  
pp. 4482-4489
Author(s):  
D M Driscoll ◽  
J G Williams
Keyword(s):  
Cyclic Amp ◽  
Nucleic Acids ◽  
Dictyostelium Discoideum ◽  
Dna Sequences ◽  
Intergenic Region ◽  
Cysteine Proteinase ◽  
Transcriptional Level ◽  
Dependent Manner ◽  
Developmentally Regulated ◽  
Reading Frame

The cysteine proteinase 1 (CP1) gene of Dictyostelium discoideum encodes a developmentally regulated sulfhydryl proteinase. We characterized the DNA sequences upstream of the CP1 gene and found a second developmentally regulated gene, which we term DG17. The translational open reading frame of the DG17 gene encoded a 458-amino-acid cysteine- and lysine-rich protein of unknown function. In several regions, the cysteine and lysine residues were arranged in a manner characteristic of the zinc-binding domains found in proteins which interact with nucleic acids. During normal development, the DG17 and CP1 genes are coordinately activated late in aggregation. The addition of exogenous cyclic AMP (cAMP) induced the premature expression of both mRNAs. By measuring the rate of specific mRNA synthesis in isolated nuclei, we showed that cAMP acted at the transcriptional level to activate both genes. The two genes were separated by 910 nucleotides and were divergently transcribed. The intergenic region was predominantly composed of A + T residues except for four short G-rich regions. These sequences coincided with the positions of four nuclease-hypersensitive sites, which appear during aggregation when the DG17 and CP1 genes are transcribed (J. Pavlovic, E. Banz, and R. W. Parish, Nucleic Acids Res. 14:8703-8722, 1986). Two of the G-rich regions formed the core of two almost identical 80-nucleotide repeats located 220 and 320 nucleotides upstream of the CP1 gene. Using the Dictyostelium transformation system, we showed that a restriction fragment containing the intergenic region was capable of directing bidirectional transcription in a cAMP-dependent manner.

scholarly journals Rates of accumulation of glycosidase activities during growth and differentiation of Dictyostelium discoideum

1975 ◽  
Vol 148 (2) ◽  
pp. 161-167 ◽  
Author(s):  
D Every ◽  
J M Ashworth
Keyword(s):  
Life Cycle ◽  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Growth Medium ◽  
Specific Activity ◽  
Growth Conditions ◽  
Cellular Protein ◽  
Total Cellular Protein ◽  
Early Differentiation ◽  
Rate Of Accumulation

1. The rates of accumulation (enzyme units/h per 10(8) cells) of a number of glycosidase activities were studied in Dictyostelium discoideum cells during the growth and differentiation phases of this organism's life cycle. 2. The rates of accumulation of the enzymes β-N-acetylglucosaminidase, α-glucosidase and β-galactosidase remain unchanged during the growth and early differentiation phases. 3. The considerable changes in specific activity of the enzymes which occur in the early differentiation phase are due to the massive loss of total cellular protein which occurs at this time. 4. Significant alterations can occur in the rates of accumulation of α-mannosidase during both the growth and differentiation phases, and since, on the onset of differentiation, β-glucosidase activity is excreted and degraded, the rate of accumulation of this enzyme differs in the growth and differentiation phases. 5. The characteristic rates of accumulation of all these glycosidases change markedly with changes in the growth conditions of the myxamoebae, and thus these rates of synthesis must be regulated independently; however, addition of cyclic AMP to the growth medium has no effect on them.

scholarly journals Two divergently transcribed genes of Dictyostelium discoideum are cyclic AMP-inducible and coregulated during development.

1987 ◽  
Vol 7 (12) ◽  
pp. 4482-4489 ◽  
Author(s):  
D M Driscoll ◽  
J G Williams
Keyword(s):  
Cyclic Amp ◽  
Nucleic Acids ◽  
Dictyostelium Discoideum ◽  
Dna Sequences ◽  
Intergenic Region ◽  
Cysteine Proteinase ◽  
Transcriptional Level ◽  
Dependent Manner ◽  
Developmentally Regulated ◽  
Reading Frame

The cysteine proteinase 1 (CP1) gene of Dictyostelium discoideum encodes a developmentally regulated sulfhydryl proteinase. We characterized the DNA sequences upstream of the CP1 gene and found a second developmentally regulated gene, which we term DG17. The translational open reading frame of the DG17 gene encoded a 458-amino-acid cysteine- and lysine-rich protein of unknown function. In several regions, the cysteine and lysine residues were arranged in a manner characteristic of the zinc-binding domains found in proteins which interact with nucleic acids. During normal development, the DG17 and CP1 genes are coordinately activated late in aggregation. The addition of exogenous cyclic AMP (cAMP) induced the premature expression of both mRNAs. By measuring the rate of specific mRNA synthesis in isolated nuclei, we showed that cAMP acted at the transcriptional level to activate both genes. The two genes were separated by 910 nucleotides and were divergently transcribed. The intergenic region was predominantly composed of A + T residues except for four short G-rich regions. These sequences coincided with the positions of four nuclease-hypersensitive sites, which appear during aggregation when the DG17 and CP1 genes are transcribed (J. Pavlovic, E. Banz, and R. W. Parish, Nucleic Acids Res. 14:8703-8722, 1986). Two of the G-rich regions formed the core of two almost identical 80-nucleotide repeats located 220 and 320 nucleotides upstream of the CP1 gene. Using the Dictyostelium transformation system, we showed that a restriction fragment containing the intergenic region was capable of directing bidirectional transcription in a cAMP-dependent manner.

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