Analysis of medaka GAP43 gene promoter activity in transgenic lines

• Published in: Gene 2023-08, Vol.879, p.147590-147590, Article 147590
• Main Authors: Kawasaki, Takashi, Fujimori, Kazuhiro E., Imada, Junko, Yuba, Shunsuke
• Format: Article
• Language: English
• Subjects: Animals; Animals, Genetically Modified - genetics; GAP43; Neuronal; Oryzias - metabolism; Promoter activity; Promoter Regions, Genetic; Spinal Cord - metabolism; Tissue specificity; Transcription Factors - genetics; Transgenic
• ISSN: 0378-1119; 1879-0038
• DOI: 10.1016/j.gene.2023.147590

•The proximal 2 k-base (b) 5′-UTR of medaka GAP43 mimicked endogenous gene expression.•Elements involved in tissue-specific expression were scattered in the 5′-UTR.•200-b upstream of the proximal 600-b region contributed to expression in telencephalon.•957 to 557b upstream of the TIS was important for maintaining promoter activity.•Sp1 and CREB1 may play important roles in the promoter activity of the medaka GAP43. We produced transgenic medaka fish lines that mimicked the expression of the GAP43 gene. Fish lines with the proximal 2-kilobase (kb) 5′-untranslated region (UTR) as the expression promoter specifically expressed enhanced green fluorescent protein (EGFP) in neural tissues, such as the brain, spinal cord, and peripheral nerves, and its expression decreased with growth, but persisted until adulthood. A functional analysis of the promoter using partially deleted UTRs revealed that functions related to neural tissue-specific promoter activity were widely distributed in the region upstream of the proximal 400-b. Furthermore, the distal half of the 2-kb UTR contributed to expression throughout the brain, while the region 400-b upstream of the proximal 600-b was strongly associated with expression in specific areas, such as the telencephalon. In addition, a region from 957 to 557b upstream of the translation initiation site was important for the long-term maintenance of promoter activity into adulthood. Among the transcription factors with recognition sequences in this region, Sp1 and CREB1 have been suggested to play important roles in the GAP43 promoter expression characteristics, such as strong expression in the telencephalon and long-term maintenance of expression.