Differential gene expression and dependence on thyroid hormones of two glyceraldehyde-3-phosphate dehydrogenases in the flatfish Senegalese sole (Solea senegalensis Kaup)

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is an essential enzyme of the glycolytic pathway. The application of large-scale genomics to Senegalese sole (Solea senegalensis) has facilitated the identification of two different genes referred to as GAPDH-1 and GAPDH-2. Main characteristics and sequence similarities with other fish and mammals are described. Phylogenetic analyses grouped both genes into two separate clusters with their mammalian counterparts as a sister clade. The expression profiles of both genes were studied during larval development and in juvenile tissues using a real-time PCR approach. In juvenile fish, GAPDH-1 was expressed mainly in muscle and GAPDH-2 in brain. During metamorphosis, GAPDH-2 mRNA levels did not change. In contrast, GAPDH-1 transcripts increased significantly between S1 and S2 metamorphic stages and reduced their levels thereafter. A treatment with the goitrogen thiourea indicated that GAPDH-1 expression was negatively regulated by thyroid hormones. The possible role of GAPDHs in metamorphosis is discussed. (c) 2007 Elsevier B.V. All rights reserved.