TY - JOUR
T1 - A polar barrier to transcription can be circumvented by remodeler-induced nucleosome translocation
AU - Gaykalova, Daria A.
AU - Nagarajavel, V.
AU - Bondarenko, Vladimir A.
AU - Bartholomew, Blaine
AU - Clark, David J.
AU - Studitsky, Vasily M.
N1 - Published by Oxford University Press.
PY - 2011/5
Y1 - 2011/5
N2 - Many eukaryotic genes are regulated at the level of transcript elongation. Nucleosomes are likely targets for this regulation. Previously, we have shown that nucleosomes formed on very strong positioning sequences (601 and 603), present a high, orientation-dependent barrier to transcription by RNA polymerase II in vitro. The existence of this polar barrier correlates with the interaction of a 16-bp polar barrier signal (PBS) with the promoter-distal histone H3-H4 dimer. Here, we show that the polar barrier is relieved by ISW2, an ATP-dependent chromatin remodeler, which translocates the nucleosome over a short distance, such that the PBS no longer interacts with the distal H3-H4 dimer, although it remains within the nucleosome. In vivo, insertion of the 603 positioning sequence into the yeast CUP1 gene results in a modest reduction in transcription, but this reduction is orientation-independent, indicating that the polar barrier can be circumvented. However, the 603-nucleosome is present at the expected position in only a small fraction of cells. Thus, the polar barrier is probably non-functional in vivo because the nucleosome is not positioned appropriately, presumably due to nucleosome sliding activities. We suggest that interactions between PBSs and chromatin remodelers might have significant regulatory potential.
AB - Many eukaryotic genes are regulated at the level of transcript elongation. Nucleosomes are likely targets for this regulation. Previously, we have shown that nucleosomes formed on very strong positioning sequences (601 and 603), present a high, orientation-dependent barrier to transcription by RNA polymerase II in vitro. The existence of this polar barrier correlates with the interaction of a 16-bp polar barrier signal (PBS) with the promoter-distal histone H3-H4 dimer. Here, we show that the polar barrier is relieved by ISW2, an ATP-dependent chromatin remodeler, which translocates the nucleosome over a short distance, such that the PBS no longer interacts with the distal H3-H4 dimer, although it remains within the nucleosome. In vivo, insertion of the 603 positioning sequence into the yeast CUP1 gene results in a modest reduction in transcription, but this reduction is orientation-independent, indicating that the polar barrier can be circumvented. However, the 603-nucleosome is present at the expected position in only a small fraction of cells. Thus, the polar barrier is probably non-functional in vivo because the nucleosome is not positioned appropriately, presumably due to nucleosome sliding activities. We suggest that interactions between PBSs and chromatin remodelers might have significant regulatory potential.
KW - Adenosine Triphosphatases/metabolism
KW - Base Sequence
KW - Chromatin Assembly and Disassembly
KW - DNA, Fungal/chemistry
KW - Metallothionein/genetics
KW - Nucleosomes/metabolism
KW - Transcription Factors/metabolism
KW - Transcription, Genetic
UR - http://www.scopus.com/inward/record.url?scp=79956057367&partnerID=8YFLogxK
UR - https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=purepublist2023&SrcAuth=WosAPI&KeyUT=WOS:000290589500010&DestLinkType=FullRecord&DestApp=WOS
U2 - 10.1093/nar/gkq1273
DO - 10.1093/nar/gkq1273
M3 - Article
C2 - 21245049
SN - 0305-1048
VL - 39
SP - 3520
EP - 3528
JO - Nucleic Acids Research
JF - Nucleic Acids Research
IS - 9
ER -