Regeneration of a lytic central vacuole and of neutral peripheral vacuolescan be visualized by green fluorescent proteins targeted to either type ofvacuoles
Gp. Di Sansebastiano et al., Regeneration of a lytic central vacuole and of neutral peripheral vacuolescan be visualized by green fluorescent proteins targeted to either type ofvacuoles, PLANT PHYSL, 126(1), 2001, pp. 78-86
Protein trafficking to two different types of vacuoles was investigated in
tobacco (Nicotiana tabacum cv SR1) mesophyll protoplasts using two differen
t vacuolar green fluorescent proteins (GFPs). One GFP is targeted to a pH-n
eutral vacuole by the C-terminal vacuolar sorting determinant of tobacco ch
itinase A, whereas the other GFP is targeted to an acidic lytic vacuole by
the N-terminal propeptide of barley aleurain, which contains a sequence-spe
cific vacuolar sorting determinant. The trafficking and final accumulation
in the central vacuole (CV) or in smaller peripheral vacuoles differed for
the two reporter proteins, depending on the cell type. Within 2 d, evacuola
ted (mini-) protoplasts regenerate a large CV. Expression of the two vacuol
ar GFPs in miniprotoplasts indicated that the newly formed CV was a lytic v
acuole, whereas neutral vacuoles always remained peripheral. Only later, on
ce the regeneration of the CV was completed, the content of peripheral stor
age vacuoles could be seen to appear in the CV of a third of the cells, app
arently by heterotypic fusion.