title: Epithelial Expression of Human ABO Blood Group Genes Is Dependent upon a Downstream Regulatory Element Functioning through an Epithelial Cell-specific Transcription Factor, Elf5.
abstract: The human ABO blood group system is of great importance in blood transfusion and organ transplantation. The ABO system is composed of complex carbohydrate structures that are biosynthesized by A- and B-transferases encoded by the ABO gene. However, the mechanisms regulating ABO gene expression in epithelial cells remain obscure. On the basis of DNase I-hypersensitive sites in and around ABO in epithelial cells, we prepared reporter plasmid constructs including these sites. Subsequent luciferase assays and histone modifications indicated a novel positive regulatory element, designated the +22.6-kb site, downstream from ABO, and this was shown to enhance ABO promoter activity in an epithelial cell-specific manner. Expression of ABO and B-antigen was reduced in gastric cancer KATOIII cells by biallelic deletion of the +22.6-kb site using the CRISPR/Cas9 system. Electrophoretic mobility shift assay and chromatin immunoprecipitation assay demonstrated that the site bound to an epithelial cell-specific transcription factor, Elf5. Mutation of the Ets binding motifs to abrogate binding of this factor reduced the regulatory activity of the +22.6-kb site. Furthermore, ELF5 knockdown with shRNA reduced both endogenous transcription from ABO and B-antigen expression in KATOIII cells. Thus, Elf5 appeared to be involved in the enhancer potential of the +22.6-kb site. These results support the contention that ABO expression is dependent upon a downstream positive regulatory element functioning through a tissue-restricted transcription factor, Elf5, in epithelial cells.
authors: From the Department of Legal Medicine, Gunma University Graduate School of Medicine, Maebashi, 371-8511 Japan, takagirie@gunma-u.ac.jp.
authors: Rie
authors: R
authors: Sano
authors: From the Department of Legal Medicine, Gunma University Graduate School of Medicine, Maebashi, 371-8511 Japan.
authors: Tamiko
authors: T
authors: Nakajima
authors: From the Department of Legal Medicine, Gunma University Graduate School of Medicine, Maebashi, 371-8511 Japan.
authors: Yoichiro
authors: Y
authors: Takahashi
authors: From the Department of Legal Medicine, Gunma University Graduate School of Medicine, Maebashi, 371-8511 Japan.
authors: Rieko
authors: R
authors: Kubo
authors: From the Department of Legal Medicine, Gunma University Graduate School of Medicine, Maebashi, 371-8511 Japan.
authors: Momoko
authors: M
authors: Kobayashi
authors: From the Department of Legal Medicine, Gunma University Graduate School of Medicine, Maebashi, 371-8511 Japan.
authors: Keiko
authors: K
authors: Takahashi
authors: the Department of Legal Medicine, Shimane University School of Medicine, Izumo, Japan, and.
authors: Haruo
authors: H
authors: Takeshita
authors: the Japanese Red Cross Central Blood Institute, Tokyo, Japan.
authors: Kenichi
authors: K
authors: Ogasawara
authors: From the Department of Legal Medicine, Gunma University Graduate School of Medicine, Maebashi, 371-8511 Japan.
authors: Yoshihiko
authors: Y
authors: Kominato
mesh_terms: D000017:ABO Blood-Group System / Q000096:biosynthesis* / Q000235:genetics; D004268:DNA-Binding Proteins; D004848:Epithelium / Q000378:metabolism*; D006801:Humans; D020014:K562 Cells; D059372:Nucleotide Motifs / Q000502:physiology*; D050783:Proto-Oncogene Proteins c-ets / Q000235:genetics / Q000378:metabolism*; D020218:Response Elements / Q000502:physiology*; D014157:Transcription Factors
chemical_list: D000017:ABO Blood-Group System; D004268:DNA-Binding Proteins; C116038:ELF5 protein, human; D050783:Proto-Oncogene Proteins c-ets; D014157:Transcription Factors
keywords: ABO; CRISPR/Cas; ETS transcription factor family; Elf5; epithelial cell; gene regulation; tissue-specific transcription factor; transcription enhancer