Molecular cloning of Indian hedgehog gene and its expression in golden pompano Trachinotus ovatus (Linnaeus 1758) larvae at different water temperatures

Abstract

The Indian hedgehog (Ihh) gene in golden pompano larvae was cloned and analyzed. The expression of Ihh during larval fish ontogeny in the first 18 days was examined, and then the expression of Ihh in fish tissues was evaluated on 18 days post hatching (DPH). Subsequently, the response of Ihh to water temperatures of 23, 26, and 290 C was compared on 12 DPH and 18 DPH. The cDNA sequence length of the golden pompano Ihh gene is 1,484 bp with an open reading frame of 1,314 bp. The Ihh gene encodes 437 amino acids and has a calculated molecular weight of 48.175 kDa and a theoretical isoelectric point of 6.22. After hatching, the expression of Ihh increased with fish age and peaked at 3 DPH. After fluctuations between 4 and 12 DPH, the expression of Ihh reached the second peak at 18 DPH. The highest expression of Ihh in tissues occurred in the fish intestine, followed in the stomach on 18 DPH. Water temperature significantly affected Ihh expression. On 12 DPH, the expression of Ihh at 23oC was significantly higher than that at 26 and 29 oC. In contrast, the expression of Ihh at 26 and 290 C was significantly higher than that at 23 oC on 18 DPH. This study detected the gene expression of Ihh at the early stage of golden pompano development and the time-dependent expression of Ihh in fish larvae is important to understand the ontogeny of bone formation in fish larvae.