What is the result of blocking thymidylate synthase regarding DNA levels?

Blocking thymidylate synthase leads to reduced DNA levels within cells due to the critical role this enzyme plays in the synthesis of thymidine, a necessary component for DNA synthesis. Thymidylate synthase is responsible for converting deoxyuridine monophosphate (dUMP) into deoxythymidine monophosphate (dTMP), which is subsequently phosphorylated to form thymidine triphosphate (dTTP). Thymidine triphosphate is vital for DNA synthesis, as it is one of the four nucleotide building blocks that are incorporated into the DNA strand during replication.

When thymidylate synthase is inhibited, the conversion of dUMP to dTMP is impeded, leading to a decreased availability of dTTP. This reduced availability directly affects the synthesis of DNA, as the cell cannot effectively produce new DNA strands due to the shortage of one of its essential building blocks. Consequently, the overall levels of DNA in the cell will decrease, which can impact cell division and proliferation, and this is particularly relevant in the context of cancer treatment, where rapidly dividing cells are the primary target.

The other answer choices do not accurately reflect the biological outcome of blocking thymidylate synthase. For example,