Characterization and promoter analysis of the mouse gene for transcriptionfactor Sp4

Transcription factor Sp4 is a member of the Sp1 family. It functions differ ently from other members of this family, such as Sp1 and Sp3, and the gene for Sp4 is transcribed in a tissue-specific manner. Recent studies in mice suggest that Sp4 might play an important role in growth, viability, and mal e fertility. We report here the isolation and characterization of the gene for Sp4 from a mouse genomic library. The mouse gene for Sp4 was about 80 l ib in length and it consisted of six exons and five introns. The promoter w as found in a CpG island and had a high G + C content. The proximal promote r contained multiple putative binding sites for the: transcription factors Spl and MAZ bur lacked a consensus TATA box. Multiple sites for the initiat ion of transcription were mapped in a GC-rich region from 286 bp to 211 bp upstream of the ATG triplet at the site of initiation of translation, and a ll of the sites were either C or G. Transfection experiments and deletion a nalysis allowed us to localize the promoter to a region that was no more th an 93 bp upstream from the first site of initiation of transcription. We al so found that ectopic expression of Sp1 and of MAZ, but not of Sp3, suppres sed expression of the Sp4 promoter in a dose-dependent manner. (C) 2001 Els evier Science B,V. All rights reserved.