Double-stranded DNA can be translocated across a planar membrane containing purified mitochondrial porin

The transport of genetic materialacross biomembranes is a process of great relevancefor several fields of study. However, much remainsto be learned about the mechanisms underlying transport,one of which implies the involvement of proteicDNA-conducting pores. Entry of genetic material intomitochondria has been observed under both physiologicaland pathological conditions. We report herethat double-stranded DNA can move through a planarbilayer membrane containing isolated mitochondrialporin (voltage-dependent anion channel). The transportis driven by the applied electrical field, and thepresence of DNA is associated with a decrease of currentconduction by the pores. The passage of DNAdoes not take place if the bilayer has not been dopedwith any protein or in the presence of both reconstitutedporin and anti-porin antibody. Translocationdoes not occur if the bilayer contains Shigella sonneimaltoporin, gramicidin A channels, or a 30 pS anionselectivechannel plus other proteins. These resultsshow that mitochondrial porin is capable of mediatingthe transport of genetic material, revealing a newproperty of this molecule and futher confirming theidea that DNA can move through proteic pores.