RNA polymerase III (Pol III) transcribes a limited set of short genes in 
eukaryotes producing abundant small RNAs, mostly tRNA. The originally defined 
yeast Pol III transcriptome appears to be expanding owing to the application of 
new methods. Also, several factors required for assembly and nuclear import of 
Pol III complex have been identified recently. Models of Pol III based on 
cryo-electron microscopy reconstructions of distinct Pol III conformations 
reveal unique features distinguishing Pol III from other polymerases. Novel 
concepts concerning Pol III functioning involve recruitment of general Pol 
III-specific transcription factors and distinctive mechanisms of transcription 
initiation, elongation and termination. Despite the short length of Pol III 
transcription units, mapping of transcriptionally active Pol III with nucleotide 
resolution has revealed strikingly uneven polymerase distribution along all 
genes. This may be related, at least in part, to the transcription factors bound 
at the internal promoter regions. Pol III uses also a specific negative 
regulator, Maf1, which binds to polymerase under stress conditions; however, a 
subset of Pol III genes is not controlled by Maf1. Among other RNA polymerases, 
Pol III machinery represents unique features related to a short transcript 
length and high transcription efficiency.