[1] Horizontal cell-to-cell transfer of mitochondria and mitochondrial genome can occur among mammalian cells in vitro and in vivo.
[1] Horizontal transfer of mitochondria is mediated by actin-rich membrane protrusions named tunneling nanotubes (TNTs).
[5] The establishment of a nanotube begins with the formation of a filopodium-like membrane protrusion that retracts after reaching the recipient cell, leaving an ultrafine structure that is separated from the substrate.
Other proposed mechanisms of transfer include membrane microvesicles, cell fusion, dendrites, and mitochondrial extrusion.
[14] All these data suggest that this phenomenon, regardless of the exact mechanisms involved, may be a fundamental physiological process well worthwhile exploring in a whole organism setting.
One of the first evidences of in vivo horizontal mitochondrial gene transfer was found in a transmissible canine venereal tumor (CTVT), highly adapted cancer transmitted during mating of feral dogs.