Open AccessSequences within the spacer region of yeast rRNA cistrons that stimulate 35S rRNA synthesis in vivo mediate RNA polymerase I-dependent promoter and terminator activities.
Author(s) -
R Mestel,
M. T. Yip,
J P Holland,
E Wang,
Josephine Kang,
Michael J. Holland
Publication year - 1989
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.9.3.1243
Subject(s) - biology , terminator (solar) , ribosomal rna , microbiology and biotechnology , upstream activating sequence , rna polymerase i , base pair , rna , t7 rna polymerase , spacer dna , rna polymerase , transcription (linguistics) , rna polymerase iii , genetics , gene , promoter , internal transcribed spacer , gene expression , escherichia coli , ionosphere , linguistics , physics , philosophy , astronomy , bacteriophage
Sequences within the spacer region of yeast rRNA cistrons stimulate synthesis of the major 35S rRNA precursor in vivo 10- to 30-fold (E. A. Elion and J. R. Warner, Cell 39:663-673, 1984). Spacer sequences that mediate this stimulatory activity are located approximately 2.2 kilobases upstream from sequences that encode the 5' terminus of the 35S rRNA precursor. By utilizing a centromere-containing plasmid carrying a 35S rRNA minigene, a 160-base-pair region of spacer rDNA was identified by deletion mapping that is required for efficient stimulation of 35S rRNA synthesis in vivo. A 22-base-pair sequence, previously shown to support RNA polymerase I-dependent selective initiation of transcription in vitro, was located 15 base pairs upstream from the 3' boundary of the stimulatory region. A 77-base pair region of spacer DNA that mediates transcriptional terminator activity in vivo was identified immediately downstream from the 5' boundary of the stimulatory region. Deletion mutations extending downstream from the 5' boundary of the 160-base-pair stimulatory region simultaneously interfere with terminator activity and stimulation of 35S rRNA synthesis from the minigene. The terminator region supported termination of transcripts initiated by RNA polymerase I in vivo. The organization of sequences that support terminator and promoter activities within the 160-base-pair stimulatory region is similar to the organization of rDNA gene promoters in higher organisms. Possible mechanisms for spacer-sequence-dependent stimulation of yeast 35S rRNA synthesis in vivo are discussed.