J. Mascarenhas et al., Specific polar localization of ribosomes in Bacillus subtilis depends on active transcription, EMBO REP, 2(8), 2001, pp. 685-689
The large subunit of ribosomes in Bacillus subtilis was tagged by generatio
n of a fusion of ribosomal protein Ll to blue fluorescent protein (BFP). Th
e fusion was fully active and localized around the nucleoids, predominantly
close to the cell poles, in growing cells. However, in stationary phase ce
lls, and in growing cells treated with rifampicin, L1-BFP was distributed t
hroughout the cells, in contrast to cells treated with chloramphenicol, in
which ribosomes still localized around nucleoids. These data show that spec
ific localization of ribosomes is not due to nucleoid exclusion, but is a d
ynamic process due to active synthesis of RNA. Dual labelling of ribosomes
and cold shock proteins (CSPs) tagged with green fluorescent protein (GFP)
revealed colocalization of both protein classes. CSPs are implicated in cou
pling of transcription with translation and may bridge the spatial separati
on of ribosomes and nucleoid-associated RNA polymerase.