Display Settings:

Format

Send to:

Choose Destination
EMBO J. 2000 Jul 3;19(13):3358-65.

Destabilization of nucleosomes by an unusual DNA conformation adopted by poly(dA) small middle dotpoly(dT) tracts in vivo.

Author information

  • 1Department of Chemistry, Meisei University, Hino, Tokyo 191-8506 and School of Pharmacy, Tokyo University of Pharmacy and Life Science, Hachioji, Tokyo 192-0392, Japan. shimizum@chem.meisei-u.ac.jp

Abstract

Poly(dA) small middle dotpoly(dT) tracts are common and often found upstream of genes in eukaryotes. It has been suggested that poly(dA) small middle dotpoly(dT) promotes transcription in vivo by affecting nucleosome formation. On the other hand, in vitro studies show that poly(dA) small middle dotpoly(dT) can be easily incorporated into nucleosomes. Therefore, the roles of these tracts in nucleosome organization in vivo remain to be established. We have developed an assay system that can evaluate nucleosome formation in yeast cells, and demonstrated that relatively longer tracts such as A(15)TATA(16) and A(34) disrupt an array of positioned nucleosomes, whereas a shorter A(5)TATA(4) tract is incorporated in positioned nucleosomes of yeast minichromosomes. Thus, nucleosomes are destabilized by poly(dA) small middle dotpoly(dT) in vivo in a length-dependent manner. Furthermore, in vivo UV footprinting revealed that the longer tracts adopt an unusual DNA structure in yeast cells that corresponds to the B' conformation described in vitro. Our results support a mechanism in which a unique poly(dA) small middle dot poly(dT) conformation presets chromatin structure to which transcription factors are accessible.

PMID:
10880448
[PubMed - indexed for MEDLINE]
PMCID:
PMC313933
Free PMC Article

Images from this publication.See all images (6)Free text

PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk