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RNA and protein synthetic patterns during germination of Polysphondylium pallidum microcysts
Abstract:
During microcyst germination in the cellular slime mould Polysphondylium pallidum, an immediate rapid increase in the rate of protein synthesis ([3H]leucine incorporation) is observed within 15 min after the initiation of germination. The data, corrected for amino acid pool changes, reveal that the rate of protein synthesis reaches its peak at 1 1/2 h, after which it decreases. A low level of RNA synthesis ([3H]uridine incorporation) is observed after 1 h and this rate increases markedly after 2 h. Analysis of the RNA species shows a low level of synthesis of all ribosomal RNA's which begins between 1 and 2 h and increases after 2 h. The synthesis of a heterogeneously distributed, poly(A)-containing fraction of RNA (presumptive mRNA) is initiated some time after 2 h and the synthesis of a small molecular weight species in the 4-5S region is observed after 3 h. Thus, it seems that Polysphondylium microcysts show sequentially initiated synthesis of RNA during germination.
Insights
Cellular slime mould protein synthesis rapidly increases during microcyst germination. RNA synthesis, including ribosomal RNA and messenger RNA, is sequentially initiated later in the germination process.
Area of Science:
- Cell Biology
- Developmental Biology
- Molecular Biology
Background:
- Cellular slime moulds like Polysphondylium pallidum exhibit complex life cycles involving microcyst germination.
- Understanding the molecular events during germination is crucial for deciphering developmental processes in these organisms.
Purpose of the Study:
- To investigate the temporal dynamics of protein and RNA synthesis during microcyst germination in Polysphondylium pallidum.
- To identify the specific types of RNA synthesized and their initiation times during this developmental transition.
Main Methods:
- Measuring protein synthesis rates via [3H]leucine incorporation, corrected for amino acid pool changes.
- Quantifying RNA synthesis rates using [3H]uridine incorporation.
- Analyzing synthesized RNA species, including ribosomal RNAs and poly(A)-containing RNA fractions.
Main Results:
- An immediate, rapid increase in protein synthesis occurs within 15 minutes of germination, peaking at 1.5 hours.
- Low-level RNA synthesis begins after 1 hour and increases significantly after 2 hours.
- Synthesis of ribosomal RNAs initiates between 1-2 hours, while presumptive mRNA and 4-5S RNA species appear after 2 and 3 hours, respectively.
Conclusions:
- Polysphondylium pallidum microcyst germination involves a rapid, early burst of protein synthesis.
- The synthesis of various RNA species, including ribosomal RNA and messenger RNA, is initiated sequentially during germination, suggesting a programmed developmental response.