TY - JOUR
T1 - The primary function of a redundant Sp1 binding site in the mouse aprt gene promoter is to block epigenetic gene inactivation
AU - Mummaneni, Padmaja
AU - Yates, Phil
AU - Simpson, James
AU - Rose, Jennifer
AU - Turker, Mitchell S.
N1 - Funding Information:
We thank Robert Burman and Brad Popovich for critical reviews of this manuscript. This work was supported by a grant from the Council for Tobacco Research.
PY - 1998/11/15
Y1 - 1998/11/15
N2 - The promoter region of the mouse adenine phosphoribosyltransferase (aprt) gene contains one nonconsensus Sp1 binding site at its 5' end followed by three consensus Sp1 binding sites. The two 3'-most binding sites are sufficient for maximal expression of aprt, suggesting that the non-consensus and consensus binding sites at the 5' end are redundant. However, the two 3' sites are not sufficient to block epigenetic inactivation, which led to the hypothesis that the redundant consensus and/or non-consensus 5' Sp1 binding sites are required to block inactivation events. To test this hypothesis, promoter region constructs were made in which the two 5' Sp1 binding sites were mutated alone or in tandem, and then each construct was tested for its ability to withstand epigenetic inactivation. A cis-acting methylation center that is normally located 1,2 kb upstream of the promoter was used to induce inactivation. The results demonstrate that the presence of the redundant consensus Sp1 binding site is required to block methylation-associated gene inactivation. Therefore, the Sp1 binding sites comprising the mouse aprt promoter have evolved two distinct functions, one to promote transcription and the other to block epigenetic inactivation.
AB - The promoter region of the mouse adenine phosphoribosyltransferase (aprt) gene contains one nonconsensus Sp1 binding site at its 5' end followed by three consensus Sp1 binding sites. The two 3'-most binding sites are sufficient for maximal expression of aprt, suggesting that the non-consensus and consensus binding sites at the 5' end are redundant. However, the two 3' sites are not sufficient to block epigenetic inactivation, which led to the hypothesis that the redundant consensus and/or non-consensus 5' Sp1 binding sites are required to block inactivation events. To test this hypothesis, promoter region constructs were made in which the two 5' Sp1 binding sites were mutated alone or in tandem, and then each construct was tested for its ability to withstand epigenetic inactivation. A cis-acting methylation center that is normally located 1,2 kb upstream of the promoter was used to induce inactivation. The results demonstrate that the presence of the redundant consensus Sp1 binding site is required to block methylation-associated gene inactivation. Therefore, the Sp1 binding sites comprising the mouse aprt promoter have evolved two distinct functions, one to promote transcription and the other to block epigenetic inactivation.
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U2 - 10.1093/nar/26.22.5163
DO - 10.1093/nar/26.22.5163
M3 - Article
C2 - 9801314
AN - SCOPUS:0032534028
SN - 0305-1048
VL - 26
SP - 5163
EP - 5169
JO - Nucleic acids research
JF - Nucleic acids research
IS - 22
ER -