Growth arrest specific gene 2 in tilapia (Oreochromis niloticus): molecular characterization and functional analysis under low-temperature stress

Growth arrest specific 2 (gas2) gene is a component of the microfilament system that plays a major role in the cell cycle, regulation of microfilaments, and cell morphology during apoptotic processes. However, little information is available on fish gas2. In this study, the tilapia (Oreochromis niloticus) gas2 gene was cloned and characterized for the first time.

The open reading frame was 1020?bp, encoding 340 amino acids; the 5′-untranslated region (UTR) was 140?bp and the 3′-UTR was 70?bp, with a poly (A) tail. The highest promoter activity occurred in the regulatory region (–3000 to –2400?bp). The Gas2-GFP fusion protein was distributed within the cytoplasm. Quantitative reverse transcription-polymerase chain reaction and western blot analyses revealed that gas2 gene expression levels in the liver, muscle, and brain were clearly affected by low temperature stress. The results of gas2 RNAi showed decreased expression of the gas2 and P53 genes.

These results suggest that the tilapia gas2 gene may be involved in low temperature stress-induced apoptosis.