Two Consecutive Zinc Fingers in Sp1 and in MAZ Are Essential for Interactions with cis-Elements

Jun Song,Hideyo Ugai,Kenji Ogawa,Yifei Wang,Akinori Sarai,Yuichi Obata,Ichiro Kanazawa,Kailai Sun,Keiichi Itakura,Kazunari K Yokoyama

doi:10.1074/jbc.m103968200

Abstract

The zinc finger proteins Sp1 and Myc-associated zinc finger protein (MAZ) are transcription factors that control the expression of various genes. Regulation of transcription by these factors is based on interactions between GC-rich DNA-binding sites (GGGCGG for Sp1 and GGGAGGG for MAZ) and the carboxyl-terminal zinc finger motifs of the two proteins. Sp1 and MAZ have three and six zinc fingers, respectively, and the details of their interactions with cis-elements remain to be clarified. We demonstrate here that Sp1 and MAZ interact with the same GC-rich DNA-binding sites, apparently sharing DNA-binding sites with each other. We found that the DNA binding activities of Sp1 and MAZ depended mainly on consecutive zinc fingers, namely the second and third zinc fingers in Sp1 and the third and fourth zinc fingers in MAZ. Furthermore, the interactions of the zinc finger proteins with the same cis-elements appear to play a critical role in the regulation of gene expression. It seems plausible that two consecutive zinc finger motifs in a zinc finger protein might be essential for interaction of the protein with DNA.

Highlights

The zinc finger proteins Sp1 and Myc-associated zinc finger protein (MAZ) are transcription factors that control the expression of various genes
The zinc finger proteins Sp1 and Myc-associated zinc finger protein (MAZ)1 are transcription factors that bind to GC-rich sequences, namely GGGCGG and GGGAGGG, respectively, to regulate the expression of various target genes
Control antibodies did not affect the mobilities of the complexes. These results indicated that Sp1 and MAZ recognized overlapping sites in the same cis-element

Summary

Introduction

The zinc finger proteins Sp1 and Myc-associated zinc finger protein (MAZ) are transcription factors that control the expression of various genes. Regulation of transcription by these factors is based on interactions between GC-rich DNA-binding sites (GGGCGG for Sp1 and GGGAGGG for MAZ) and the carboxyl-terminal zinc finger motifs of the two proteins. The zinc finger proteins Sp1 and Myc-associated zinc finger protein (MAZ) are transcription factors that bind to GC-rich sequences, namely GGGCGG and GGGAGGG, respectively, to regulate the expression of various target genes. MAZ was first identified as a transcription factor that bound to a GA box (GGGAGGG) at the ME1a1 site of the c-myc promoter and to the CT-element of the c-myc gene [11] It is a zinc finger protein with six C2H2-type zinc fingers at the carboxyl terminus, a proline-rich region, and three alanine repeats. It can regulate the expression of numerous genes, such as c-myc [11, 13], genes for insulin I and II [14], the gene for CD4 [15], the gene for the serotonin receptor [16], and the gene for nitric oxide synthase [17]

Methods

Results

Conclusion