Cloning and Functional Characterization of the 5′-Flanking Region of the Human Monocyte Chemoattractant Protein-1 Receptor (CCR2) Gene

• Published in: The Journal of biological chemistry 1999-02, Vol.274 (8), p.4646
• Main Authors: Keizo Yamamoto, Hideo Takeshima, Kazuya Hamada, Mitsuyoshi Nakao, Takeshi Kino, Toru Nishi, Masato Kochi, Jun-Ichi Kuratsu, Teizo Yoshimura, Yukitaka Ushio
• Format: Article
• Language: English
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.274.8.4646

The human monocyte chemoattractant protein-1 receptor designated hCCR2 is an essential co-receptor in cell entry by the human immunodeficiency virus as well as a receptor for monocyte chemoattractant protein-1, a member of the family of C-C chemokines that mediate monocyte chemotaxis. To elucidate the molecular mechanisms underlying the transcriptional regulation of hCCR2, we cloned and sequenced the hCCR2 gene; it was approximately 8 kilobase pairs in length and consisted of three exons divided by two introns. In the 5′-flanking region, there were the typical mammalian promoter consensus elements, a CAAT box and a TATA box, resulting in a single transcription initiation site. In addition, we found clustered tissue-specific cis -regulatory elements such as GATA consensus sequences, Oct-1 binding sequences, and CAAT/enhancer-binding protein binding sequences. Luciferase assays with various promoter deletions and gel mobility shift assays indicated that three cis -regulatory elements located within the region from −89 to +118 are required for basal activity in THP-1 cells. One element is an octamer sequence 36-base pair upstream from the TATA box; it binds mainly to Oct-1 and is capable of increasing transcriptional activity. The other two elements, which are tandem recognition sites of the CAAT/enhancer-binding protein family, are located in the 5′-untranslated region and account for the transcriptional activation as well as the tissue specificity of hCCR2.