Fluctuations in deoxyribo- and ribonucleoside triphosphate pools during the mitotic cycle of Physarum polycephalum

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• The cell cycle involves precise regulation of DNA replication and cell division.
• Nucleoside triphosphates are essential building blocks for DNA and RNA synthesis.
• Understanding nucleotide pool dynamics is crucial for comprehending cell cycle control.

Purpose of the Study:

• To investigate fluctuations in deoxyribonucleoside triphosphates (dNTPs) and ribonucleoside triphosphates (rNTPs) during the synchronous mitotic cycle of Physarum polycephalum.
• To correlate these nucleotide pool changes with specific cell cycle phases, particularly DNA synthesis and mitosis.

Main Methods:

• Synchronous culture of the slime mould Physarum polycephalum.
• Measurement of intracellular pools of deoxyribonucleoside triphosphates (dATP, dCTP, dGTP, dTTP) and ribonucleoside triphosphates.
• Analysis of nucleotide pool fluctuations in relation to the mitotic cycle and DNA synthesis initiation.

Main Results:

• Deoxyribonucleoside triphosphate pools (dTTP, dATP, dCTP, dGTP) showed significant fluctuations, expanding before DNA synthesis initiation and decreasing during early S phase.
• Ribonucleoside triphosphate pools exhibited increases during mitosis and at later time points (1 h and 5 h) post-mitosis.
• The most pronounced dNTP fluctuations were observed just before and after the onset of DNA synthesis.

Conclusions:

• Nucleotide pool dynamics are tightly regulated during the Physarum polycephalum cell cycle.
• Specific temporal patterns of dNTP and rNTP pool expansion and contraction correlate with key cell cycle events like DNA synthesis and mitosis.
• These findings contribute to the understanding of molecular mechanisms governing cell proliferation.