Molecular Characterization and Expression Changes of the Gene in Response to Hypoxia in .

Hypoxia is a unique environmental stress, which not only reflects the insufficient oxygen supply of cells and tissues, but also occurs in various physiological and pathological environments. Mitophagy as a selective autophagy can recover and utilize damaged organelles and misfolded proteins to ensure normal cell functions and promote cell survival. Bcl2l13 (B-cell lymphoma-2 like 13) is reported to induce mitophagy as a functional mammalian homolog of Atg32. However, the function of the gene is still unclear in fish. Here the sequence and structure of the gene in were identified and showed that contained an open reading frame (ORF) of 1458 bp for encoding 485 aa. Amino acid sequence analysis indicated that Bcl2l13, as a typical anti-apoptotic protein of the Bcl2 family, contained four BH domains, one BHNo domain, and one TM domain. Further study showed that Bcl2l13 was mainly located in the mitochondria, while its localization was changed within the whole cell after the TM domain was deleted. Real-time PCR analysis revealed that showed higher expression levels in early embryos. After hypoxia treatment, the mRNA levels of the and autophagy-related genes were significantly up-regulated in most detected tissues, and the transcription was regulated by Hif-1α mediated pathway. Additionally, the transcription activity of the promoter was further analyzed using luciferase reporter assays and showed the highest activity in the promoter region from -475 to +111. These results indicated that may play important roles in embryogenesis and hypoxia mediated autophagy in fish.