Ch. Lee et al., Targeting a SWI/SNF-related chromatin remodeling complex to the beta-globin promoter in erythroid cells, P NAS US, 96(22), 1999, pp. 12311-12315
Citations number
41
Categorie Soggetti
Multidisciplinary
Journal title
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Chromatin remodeling complexes such as the SWI/SNF complex make DNA accessi
ble to transcription factors by disrupting nucleosomes. However, it is not
known how such complexes are targeted to the promoter. For example, a SWI/S
NF1-like chromatin remodeling complex erythroid Kruppel-like factor (EKLF)
coactivator-remodeling complex 1 (E-RC1) disrupts the nucleosomes over the
human beta-globin promoter in an EKLF-dependent manner. However, it is not
known whether E-RC1 is targeted specifically to the beta-globin promoter or
whether E-RC1 is randomly targeted, but its activity is evident only at th
e beta-globin promoter. Because E-RC1 cannot remodel chromatin over the bet
a-globin promoter without EKLF in vitro, it has been proposed that SWI/SNF1
-like complexes such as E-RC1 are targeted specifically to the promoter by
selectively interacting with promoter-associated transcription factors such
as EKLF. In this report, we test this hypothesis in the cellular context b
y using the ProteIN POsition Identification with Nuclease Tail (PIN*POINT)
assay. We find that the Brahma-related gene (BRG) 1 and BRG1-associated fac
tor (BAF) 170 subunits of E-RC1 are both recruited near the transcription i
nitiation site of the beta-globin promoter. On transiently transfected temp
lates, both the locus control region and the EKLF-binding site are importan
t for their recruitment to the beta-globin promoter in mouse erythroleukemi
a cells. When the beta-globin promoter was linked to the cytomegalovirus en
hancer, the E-RC1 complex was not recruited, suggesting that recruitment of
the E-RC1 complex is not a general property of enhancers.