The SM19 gene, required for duplication of basal bodies in Paramecium, encodes a novel tubulin, eta-tubulin

Curr Biol. 2000 Nov 16;10(22):1451-4. doi: 10.1016/s0960-9822(00)00804-6.


The discovery of delta-tubulin, the fourth member of the tubulin superfamily, in Chlamydomonas [1] has led to the identification in the genomes of vertebrates and protozoa of putative delta homologues and of additional tubulins, epsilon and zeta [2-4]. These discoveries raise questions concerning the functions of these novel tubulins, their interactions with microtubule arrays and microtubule-organising centres, and their evolutionary status. The sm19-1 mutation of Paramecium specifically inhibits basal body duplication [5] and causes delocalisation of gamma-tubulin, which is also required for basal body duplication [6]. We have cloned the SM19 gene by functional complementation and found that it encodes another new member of the tubulin superfamily. SM19p, provisionally called eta-tubulin (eta-tubulin), shows low sequence identity with the tubulins previously identified in Paramecium, namely, alpha [7], beta [8], gamma [6], delta (this work) and epsilon (P. Dupuis-Williams, personal communication). Phylogenetic analysis indicated that SM19p is not consistently grouped with any phylogenetic entity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cloning, Molecular
  • DNA, Complementary
  • Genes, Protozoan / physiology*
  • Humans
  • Molecular Sequence Data
  • Open Reading Frames
  • Paramecium / genetics
  • Paramecium / physiology*
  • Phylogeny
  • Protozoan Proteins / classification
  • Protozoan Proteins / genetics*
  • Sequence Homology, Amino Acid
  • Tubulin / classification
  • Tubulin / genetics*


  • DNA, Complementary
  • Protozoan Proteins
  • Tubulin