Validation of zebrafish (Danio rerio) reference genes for quantitative real-time RT-PCR normalization.

The normalization of quantitative real time RT-PCR (qRT-PCR) is important to obtain accurate gene expression data. The most common method for qRT-PCR normalization is to use reference, or housekeeping genes. However, there is emerging evidence that even reference genes can be regulated under different conditions. qRT-PCR has only recently been used in terms of zebrafish gene expression studies and there is no validated set of reference genes. This study characterizes the expression of nine possible reference genes during zebrafish embryonic development and in a zebrafish tissue panel. All nine reference genes exhibited variable expression. The beta-actin, EF1alpha and Rpl13alpha genes comprise a validated reference gene panel for zebrafish developmental time course studies, and the EF1alpha, Rpl13alpha and 18S rRNA genes are more suitable as a reference gene panel for zebrafish tissue analysis. Importantly, the zebrafish GAPDH gene appears unsuitable as reference gene for both types of studies.