TY - JOUR
T1 - Virtually the entire Xenopus laevis rDNA multikilobase intergenic spacer serves to stimulate polymerase I transcription
AU - Mougey, Edward B.
AU - Pape, Louise K.
AU - Sollner-Webb, Barbara
PY - 1996
Y1 - 1996
N2 - The promoter-distal half of the spacer separating the tandem Xenopus laevis rRNA genes consists of '0' and '1' repetitive elements that have been considered unimportant in polymerase I transcriptional activation. Utilizing oocyte microinjection, we now demonstrate that the 0/1 region, as well as its component 0 and 1 repeats, substantially stimulate transcription from a ribosomal promoter in cis and inhibit transcription when located in trans. Both the cis and trans responses increase linearly with increasing numbers of 0 or 1 repeats until saturation is approached. The 0/1 block and its component elements stimulate transcription in both orientations, over distances, and when placed downstream of the initiation site, properties for which the 60/81-base pair (bp) repeats have been defined as polymerase I enhancers. In their natural promoter-distal rDNA location, the 0/1 repeats can stimulate transcription from the rRNA gene promoter, above the level afforded by the intervening 60/81-bp repeats and spacer promoter. In addition, as with the 60/81-bp repeats, the 0/1 repeats bind a factor in common with the rDNA promoter. Thus, the entire X. laevis rDNA intergenic spacer (the 0 repeats, 1 repeats, spacer promoter repeats, and 60/81-bp repeats) acts together to enhance ribosomal transcription.
AB - The promoter-distal half of the spacer separating the tandem Xenopus laevis rRNA genes consists of '0' and '1' repetitive elements that have been considered unimportant in polymerase I transcriptional activation. Utilizing oocyte microinjection, we now demonstrate that the 0/1 region, as well as its component 0 and 1 repeats, substantially stimulate transcription from a ribosomal promoter in cis and inhibit transcription when located in trans. Both the cis and trans responses increase linearly with increasing numbers of 0 or 1 repeats until saturation is approached. The 0/1 block and its component elements stimulate transcription in both orientations, over distances, and when placed downstream of the initiation site, properties for which the 60/81-base pair (bp) repeats have been defined as polymerase I enhancers. In their natural promoter-distal rDNA location, the 0/1 repeats can stimulate transcription from the rRNA gene promoter, above the level afforded by the intervening 60/81-bp repeats and spacer promoter. In addition, as with the 60/81-bp repeats, the 0/1 repeats bind a factor in common with the rDNA promoter. Thus, the entire X. laevis rDNA intergenic spacer (the 0 repeats, 1 repeats, spacer promoter repeats, and 60/81-bp repeats) acts together to enhance ribosomal transcription.
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U2 - 10.1074/jbc.271.43.27138
DO - 10.1074/jbc.271.43.27138
M3 - Article
C2 - 8900206
AN - SCOPUS:0029861293
SN - 0021-9258
VL - 271
SP - 27138
EP - 27145
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 43
ER -