Transcriptional Regulation of the Human PAX6 Gene Promoter

doi:10.1074/jbc.272.6.3430

Transcriptional Regulation of the Human PAX6 Gene Promoter*

Zheng-Ping Xu and
Grady F. Saunders^‡

From the Department of Biochemistry and Molecular Biology, The University of Texas, M. D. Anderson Cancer Center, Houston, Texas 77030

^‡ To whom correspondence should be addressed:
Dept. of Biochemistry and Molecular Biology, Box 117, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030.
Tel.: 713-792-2690; Fax: 713-790-0329; E-mail: sa08301{at}odin.mdacc.tmc.edu

Abstract

PAX6, a member of the highly conserved paired-type homeobox gene family, is expressed in a spatially and temporally restricted pattern during early embryogenesis, and its mutation is responsible for human aniridia. Here we examined the transcriptional regulation of the PAX6 gene by transient transfection assays and identified multiple cis-regulatory elements that function differently in different cell lines. The transcriptional initiation site was identified by RNase protection and primer extension assay. Examination of the genomic DNA sequence indicated that the PAX6 promoter has a TATA like-box (ATATTTT) at −26 base pairs (bp), and two CCAAT boxes are positioned at −70 and −100 bp. A 38-bp poly(CA) sequence was located 992 bp upstream from the initiation site. Transient transfection assays in glioblastoma cells and leukemia cells indicate that a 92-bp region was required for basal level PAX6 promoter activity. A negative transcriptional element, silencer (bases −1518 to −1268), functioned differently in different cell lines. The activation of the promoter is positively correlated with the expression of PAX6 transcripts in all cells tested. These results indicate that a cis-regulatory element or elements is responsible for selective activation of the PAX6 promoter in cells that can express PAX6 mRNA.

Footnotes

↵* This work was supported by Grants EY09675, EY10608, and CA16672 from the National Institutes of Health and Texas Grant ARP-000015-046. The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The nucleotide sequence(s) reported in this paper has been submitted to the GenBank™/EMBL Data Bank with accession number(s) U63833[GenBank].
↵¹ The abbreviations used are:

kb

kilobase(s)

bp

base pair(s)

CAT

chloramphenicol acetyltransferase

PCR

polymerase chain reaction

AP2

activator protein-2

GCF

GC factor

TCF

T cell-specific transcription factor.
↵² Z.-P. Xu and G. F. Saunders, unpublished data.
- Received September 27, 1996.
- Revision received November 22, 1996.