Nested genes CDA12 and CDA13 encode proteins associated with membrane trafficking in the ciliate Tetrahymena thermophila

Eukaryot Cell. 2009 Jun;8(6):899-912. doi: 10.1128/EC.00342-08. Epub 2009 Mar 13.


We describe a novel pair of nested genes, CDA12 and CDA13, from Tetrahymena thermophila. Both are implicated in membrane trafficking associated with cell division and conjugation. Green fluorescent protein localization reveals Cda12p decoration of diverse membrane-bound compartments, including mobile, subcortical tubulovesicular compartments; perinuclear vesicles; and candidates for recycling endosomes. Cda13p decorates intracellular foci located adjacent to cortically aligned mitochondria and their neighboring Golgi networks. The expression of antisense CDA12 RNA in transformants produces defects in cytokinesis, macronuclear segregation, and the processing of pinosomes to downstream compartments. Antisense CDA13 RNA expression produces a conjugation phenotype, resulting in the failure of mating pairs to separate, as well as failures in postconjugation cytokinesis and macronuclear fission. This study offers insight into the membrane trafficking events linking endosome and Golgi network activities, cytokinesis, and karyokinesis and the unique membrane-remodeling events that accompany conjugation in the ciliate T. thermophila. We also highlight an unusual aspect of genome organization in Tetrahymena, namely, the existence of nested, antisense genes.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Cell Membrane / genetics
  • Cell Membrane / metabolism*
  • Cytokinesis
  • Molecular Sequence Data
  • Nested Genes*
  • Protein Transport
  • Protozoan Proteins / genetics*
  • Protozoan Proteins / metabolism*
  • Tetrahymena thermophila / cytology
  • Tetrahymena thermophila / genetics*
  • Tetrahymena thermophila / metabolism*


  • Protozoan Proteins

Associated data

  • GENBANK/AY337263