Q5: Contrasting Molecular Tools – Epitranscriptomic Regulation of mRNA Contrast the roles of the m6A "Writer" complex (METTL3/METTL14) and the "Reader" protein YTHDF2 in governing mRNA metabolism. If a researcher used a small-molecule inhibitor to block the "Eraser" (FTO) in a neuronal cell line, deduce the likely effect on the half-life and stability of m6A-modified transcripts. Would this inhibition result in "RNA restructuring" via an m6A-switch mechanism, or would it primarily lead to accelerated decay?

What does the m6A Writer complex (METTL3/METTL14) do?

Installs N6-methyladenosine (m6A) modification on mRNA transcripts. METTL3 is the catalytic core; METTL14 provides structural stabilization.

What does the YTHDF2 Reader protein do?

Recognizes and binds existing m6A marks via its YTH domain, then recruits the CCR4-NOT deadenylase complex to promote mRNA decay.

What happens to m6A-modified transcripts when FTO (the Eraser) is blocked?

Increased global m6A levels (hypermethylation), leading to decreased mRNA stability and shortened half-life.

Why does blocking FTO decrease mRNA stability?

Hypermethylated transcripts have more m6A sites for YTHDF2 binding, increasing recruitment of the CCR4-NOT decay machinery.

Does FTO inhibition primarily cause RNA restructuring via m6A-switch or accelerated decay?

Primarily accelerated decay.

What is the m6A-switch mechanism?

m6A induces structural changes in RNA to expose binding motifs for readers like HNRNPC.

Why does FTO inhibition lead to accelerated decay rather than RNA restructuring?

Because the primary metabolic outcome governing transcript stability in the m6A system is accelerated decay via YTHDF2, not structural switching.

What is the normal function of FTO?

Removes m6A marks from transcripts (acts as an eraser).

What is the three-step causal chain following FTO inhibition with FB-23?

1) Hypermethylation (m6A marks cannot be removed). 2) Increased reader binding (more m6A sites for YTHDF2). 3) Decreased mRNA stability and shortened half-life