The tubulin repertoire of Caenorhabditis elegans sensory neurons and its context‑dependent role in process outgrowth

Microtubules contribute to many cellular processes, including transport, signaling, and chromosome separation during cell division. They comprise αβ‑tubulin heterodimers arranged into linear protofilaments and assembled into tubes. Eukaryotes express multiple tubulin isoforms, and there has been a longstanding debate as to whether the isoforms are redundant or perform specialized roles as part of a tubulin code. Here we use the well‑characterized touch receptor neurons (TRNs) of Caenorhabditis elegans to investigate this question through genetic dissection of process outgrowth both in vivo and in vitro. With single‑cell RNA-seq, we compare transcription profiles for TRNs with those of two other sensory neurons and present evidence that each sensory neuron expresses a distinct palette of tubulin genes. In the TRNs, we analyze process outgrowth and show that four tubulins (tba‑1, tba‑2, tbb‑1, and tbb‑2) function partially or fully redundantly, whereas two others (mec‑7 and mec‑12) perform specialized, context‑dependent roles. Our findings support a model in which sensory neurons express overlapping subsets of tubulin genes whose functional redundancy varies among cell types and in vivo and in vitro contexts.