THE SPATIAL-TEMPORAL EXPRESSION PATTERNS OF NRF AND THEIR DIFFERENT EFFECTS ON REGULATION OF ZYMOGENS IN ZEBRAFISH

The nuclear factor-erythroid-2 (nfe2)-related factor (Nrf) regulates genes involving in antioxidative stress response, anti-inflammatory response, and detoxification of heavy metals. Six nrf genes (nfe2, nrf1a, nrf1b, nrf2a, nrf2b and nrf3) were found in zebrafish based on blasting of the GenBank. The phylogenetic tree analysis indicated that the vertebrate Nrf proteins were conserved during the evolution of species, in spite of the fact that the nrf1 and nrf2 respectively have two duplicates, resulted from the whole-genome duplication in teleosts. The results of whole mount in situ hybridization indicated that all 6 genes expressed at the one cell stage, and their expressions were ubiquitous in early stage of embryonic development. At 72 hpf, nrf1b, nrf2a, nrf2b, nrf3 and nfe2 were specifically expressed in head, part of the trunk and gut, and nrf2b was slightly expressed in the spinal cord. In general, the expressional sites of six nrf gene were overlap. Strikingly, over-expression of Nrf1a, Nrf2a, Nrf2b and Nfe2 induced tryl expression, however Nrf1b and Nrf3 overexpression reduced tryl expression with a dosage dependent pattern. These studies provide foundational data for functional superposition and complementarities among these six nrf genes.