Catalytic tRNA acetyltransferase subunit of the elongator complex which is required for multiple tRNA modifications, including mcm5U (5-methoxycarbonylmethyl uridine), mcm5s2U (5-methoxycarbonylmethyl-2-thiouridine), and ncm5U (5-carbamoylmethyl uridine) (By similarity). In the elongator complex, acts as a tRNA uridine(34) acetyltransferase by mediating formation of carboxymethyluridine in the wobble base at position 34 in tRNAs (By similarity). Involved in neurogenesis (PubMed:18996918). Involved in somite development (PubMed:32023806). acetyl-CoA + H2O + S-adenosyl-L-methionine + uridine(34) in tRNA = 5'-deoxyadenosine + carboxymethyluridine(34) in tRNA + CoA + 2 H(+) + L-methionine Binds 1 [4Fe-4S] cluster. The cluster is coordinated with 3 cysteines and an exchangeable S-adenosyl-L-methionine. tRNA modification; 5-methoxycarbonylmethyl-2-thiouridine-tRNA biosynthesis. Component of the elongator complex. Morpholino knockdown in embryos results in reduced tRNA modification with decreased levels of mcm5s2U (5-methoxycarbonylmethyl-2-thiouridine) (PubMed:32023806). Morphant larvae display a ventrally curved body where somites present a distortion of their typical chevron shape, being rounded with a different angle compared to controls (PubMed:32023806). Morphants also show disruption of the horizontal myoseptum, diminished somite area, disorganised muscle fibers, a small neural tube and reduced Shh signaling activity (PubMed:32023806). One study has shown that morpholino knockdown in embryos at 27 hpf results in abnormal motor neuron axonal branching and length (PubMed:18996918). However, another study observed shortening in only 5% of motor neurons at 27 hpf and normal length by 48 hpf (PubMed:32023806). Belongs to the ELP3 family. The elongator complex was originally thought to play a role in transcription elongation. However, it is no longer thought to play a direct role in this process and its primary function is thought to be in tRNA modification.