Zoological Studies

Genomic Structure and Promoter Region of c-fos Gene of Round-spotted Pufferfish, Tetraodon nigroviridis (Syn. T. fluviatilis)

Mau-Sun Chang, Jiann-Horng Leu,·Chen-Wen Yao, Fore-Lien Huang and Chang-Jen Huang (1997) Ge­nomic structure and promoter region of c-fos gene of round-spotted pufferfish, Tetraodon nigroviridis (Syn T. fluviatilis). Zoological Studies 36(3): 159-169. The round-spotted pufferfish c-fos gene was isolated from a liver genomic library. Complete DNA sequences, including 0.75-kb of the promoter region were deter­ mined. Our data indicate that this gene is composed of 4 exons and 3 introns spanning about 3 kb. This gene encodes a protein of 374 amino acids with a molecular mass of 42 262 Da. The amino acid sequence identities between this puffer fish c-fos protein and fugu (another pufferfish species), human, mouse, and chicken c-fos protein are 90%, 58%, 58%, and 53%, respectively. Two potential transcription initiation sites were located by primer extension analysis. Examination of 0.75-kb of a 5'-flanking sequence revealed potential binding sites for a variety of transcription factors such as CREB, E2A, Ets-1, GATA-1, HNF-5, c-Myb, and Sp1. When the 0.9-kb DNA fragment (-746 to +153) was placed upstream of the chloramphenicol acetyl­ transferase (CAT) reporter gene and transfected into a carp CF cell line, it could drive the synthesis of CAT enzyme 2.7 times more efficiently than could the RSV promoter. Although lacking the known serum-response element, the CAT activity of this region still could be induced by serum