SHORT COMMUNICATION Genomic Organization of the Human ELF3 (ESE-1/ESX) Gene, A Member of the Ets Transcription Factor Family, and Identification of a Functional Promoter Peter Oettgen,* Marcello Barcinski,† Jay Boltax,* Peggy Stolt,* Yasmin Akbarali,* and Towia A. Libermann* ,1 * New England Baptist Bone and Joint Institute, Beth Israel Deaconess Medical Center, and Harvard Medical School, Boston, Massachusetts 02215; and †Department of Parasitology, University of Sao Paulo, Sao Paulo, Brazil 05508-900 Received July 21, 1998; accepted November 12, 1998 We recently isolated a novel member of the Ets tran- scription factor/oncogene family, ESE-1/ESX/ELF3, with features distinct from any other Ets-related fac- tor. ELF3 is the prototype of a new subclass of Ets factors, contains two DNA-binding domains, and, in contrast to any known Ets factor, is expressed exclu- sively in epithelial cells. ELF3 expression is induced during differentiation of the epidermis, indicating a role in the regulation of terminal differentiation genes in the epidermis. Due to the important role that other Ets factors play in cellular differentiation, ELF3 is expected to be a critical regulator of epithelial gene expression. We report here the cloning and the struc- tural organization of the human ELF3 gene. The hu- man ELF3 gene contains nine exons, which span ap- proximately 5.8 kb of genomic DNA. Intron/exon borders and number of exons are almost identical to those in the mouse ELF3 gene. Comparison of the im- mediate promoter regions of the human and mouse ELF3 genes demonstrates the presence of TATA and CCAAT boxes as well as potential binding sites for Ets factors and NF-B. Transfection experiments demon- strate that a 1.5-kb fragment of the 5 upstream region acts as a strong promoter in two epithelial cell lines. © 1999 Academic Press The rapidly expanding Ets gene family currently consists of approximately 30 members, that function as transcription factors under physiological conditions (9, 13, 25). Ets factors are crucial for transcriptional con- trol of stringently regulated genes such as genes in- volved in tissue development, differentiation, angio- genesis, cell cycle control, and cell proliferation and function as both transcriptional enhancers and repres- sors (9, 13, 25). Their transactivation capacity is highly regulated by protein–protein interactions with other transcription factors and phosphorylation by various inducible kinases. The relevance of Ets factors during development has been substantiated by gene-targeting strategies in mice (2, 21, 24). Several members of the Ets family also have emerged as apparent oncogenes due to distinct chromosomal translocations in different types of human cancer, and many pathological features of Down syndrome have been directly correlated with overexpression of Ets-2, which is located within the minimal Down syndrome genetic region on chromo- some 21 (6 – 8, 17–20, 22). All Ets factors share a highly conserved DNA-binding domain, the ETS domain, whereas other domains are unique or shared only among a subclass of the Ets family (9, 12, 13, 25). We and others recently cloned a novel ets factor, ELF3 (also called ESE-1, ESX, jen, and ERT), whose expression appears to be restricted to epithelial cells (1, 4, 5, 13, 14, 23). ELF3 is expressed in many, but not all, epithelial cell types and plays a role during termi- nal differentiation of the epidermis (1, 13). Apparent target genes for ELF3 include at least three terminal differentiation markers, SPRR2A, transglutaminase 3, and profillaggrin, as well as the HER-2 gene, which is overexpressed in many breast cancers and other tu- mors (1, 4, 13). The epithelial-specific expression pat- tern of ELF3 is unique among members of the Ets family, and to date very few epithelial-specific tran- scription factors have been identified. Epithelial-spe- cific gene regulation is crucial in the earliest stages of embryogenesis and continues throughout adult life. Defects in epithelial cell differentiation and function result in cancer and many other diseases. Cloning of ELF3 has opened up a new avenue to explore epithelial cell differentiation, and the ELF3 gene is located on a human chromosome region, 1q32.1– q32.2, frequently altered in several types of cancers (4, 14). Thus, to 1 To whom correspondence should be addressed at Department of Medicine, Beth Israel Deaconess Medical Center, 330 Brookline Av- enue, Boston, MA 02215. Telephone: (617) 667-3393. Fax: (617) 975- 5299. E-mail: tliberma@bidmc.harvard.edu. All articles available online at http://www.idealibrary.com on Genomics 55, 358 –362 (1999) Article ID geno.1998.5681 358 0888-7543/99 $30.00 Copyright © 1999 by Academic Press All rights of reproduction in any form reserved.