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A microcyst-overproducing mutant of Polysphondylium pallidum
Abstract:
A mutant, PN6017, of the cellular slime mold Polysphondylium pallidum was selected by cell-surface labeling with a monoclonal antibody, mAb 293, and fluorescence-activated cell sorting. The antibody was directed against an L-fucose-containing epitope on glycoproteins, designated ep 293, and the mutant showed reduced and delayed expression of this epitope. PN6017 was distinguished from other mutants of this kind by extensive microcyst formation on agar plates under conditions where the wild type formed only sparse microcysts. In suspension cultures transformation of cells into microcysts was negligible in the wild type, and close to 100% in the mutant. Under these conditions microcyst formation in the mutant began at 5-7 h of starvation. At the same time expression of ep 293 and also of a developmentally regulated cytoplasmic protein, pallidin, became detectable. This coincidence in time suggests that microcyst formation in PN6017 is coupled to the same control mechanism as the two other developmentally regulated processes.
Insights
A Polysphondylium pallidum mutant, PN6017, exhibits enhanced microcyst formation. This process is linked to the expression of L-fucose-containing glycoproteins (ep 293) and pallidin during starvation.
Area of Science:
- Cell biology
- Developmental biology
- Microbiology
Background:
- Cellular slime molds like Polysphondylium pallidum undergo developmental processes.
- Microcyst formation is a key developmental stage in some slime molds.
- Specific cell-surface glycoproteins and cytoplasmic proteins are involved in slime mold development.
Purpose of the Study:
- To investigate a mutant (PN6017) of Polysphondylium pallidum with altered cell-surface glycoprotein expression.
- To characterize the microcyst formation process in the PN6017 mutant.
- To explore the relationship between microcyst formation and the expression of specific developmental markers.
Main Methods:
- Selection of a mutant (PN6017) using monoclonal antibody (mAb 293) labeling and fluorescence-activated cell sorting.
- Analysis of microcyst formation on agar plates and in suspension cultures under starvation conditions.
- Monitoring the expression of the L-fucose-containing epitope (ep 293) and the cytoplasmic protein pallidin.
Main Results:
- The PN6017 mutant displayed reduced and delayed expression of the ep 293 epitope.
- PN6017 exhibited significantly increased microcyst formation compared to the wild type, both on agar and in suspension.
- Microcyst formation in the mutant initiated at 5-7 hours of starvation, coinciding with the detection of ep 293 and pallidin expression.
Conclusions:
- The PN6017 mutant is characterized by altered expression of a specific L-fucose-containing glycoprotein epitope.
- Enhanced microcyst formation in PN6017 suggests a potential regulatory role for ep 293 and pallidin.
- The findings indicate that microcyst formation in this mutant is coupled to the same control mechanisms regulating ep 293 and pallidin expression during development.