Open AccessRNA Polymerase III Transcription Complexes on Chromosomal 5S rRNA Genes In Vivo: TFIIIB Occupancy and Promoter Opening
Author(s) -
Giovanna Costanzo,
Sylvie Camier,
P. Carlucci,
L. Burderi,
Rodolfo Negri
Publication year - 2001
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.21.9.3166-3178.2001
Subject(s) - biology , transcription (linguistics) , microbiology and biotechnology , footprinting , rna polymerase i , rna polymerase iii , rna polymerase , rna , genetics , gene , transcription factor , philosophy , linguistics
Quantitative analysis of multiple-hit potassium permanganate (KMnO(4)) footprinting has been carried out in vivo on Saccharomyces cerevisiae 5S rRNA genes. The results fix the number of open complexes at steady state in exponentially growing cells at between 8 and 17% of the 150 to 200 chromosomal copies. UV and dimethyl sulfate footprinting set the transcription factor TFIIIB occupancy at 23 to 47%. The comparison between the two values suggests that RNA polymerase III binding or promoter opening is the rate-limiting step in 5S rRNA transcription in vivo. Inhibition of RNA elongation in vivo by cordycepin confirms this result. An experimental system that is capable of providing information on the mechanistic steps involved in regulatory events in S. cerevisiae cells has been established.