STUDY ON EXPRESSION PATTERN AND FUNCTION OF ZEBRAFISH HO1

This paper has studied the function of heme oxygenase 1 (HO1) in the development of zebrafish. Zebrafish HO1 contains heme oxygenase domain, heme binding signature, five histidine residues and hydrophobic segment at carboxyl terminus. Analysis of the deduced amino acid sequences revealed zebrafish HO1 shared 44.1%86.8% similarity with known sequences from other species. Analyzing embryos of different development stages by RT-PCR showed that zebrafish HO1 existed in unfertilized eggs. Its level increased from 24hpf and remained a high level expression until 72hpf. The tissue expression pattern analysis showed that zabrafish HO1 was expressed ubiquitously and the expression in brain, heart, gill and liver was obviously higher than others. Whole-mount in situ hybridization showed that HO1 transcript exists in yolk syncytial layer, blood and eyes during embyonic development. Using overexpression and knock down technology, we found that over-expression of HO1 had no apparent effect on the early development of zebrafish. Knocked down of HO1 gene by HO1 MO made the embryo development retarded. The abnormality and lethal rates of embryos after MO treatment were significantly increased compared with control. The level of IGF1 and IGFBP1 mRNA changed significantly after HO1 was knocked down. These results showed that HO1 can regulate of zebrafish embryonic development through IGF signaling.