THE SPATIO TEMPORAL EXPRESSION OF EMBRYO/LARVAL HEMOGLOBIN GENE IN GYMNOCYPRIS ECKLONI

To investigate the hemoglobin switching and hematopoietic development of teleost fish, the embryo/larval hemoglobin gene repertoire was determined in Gymnocypris eckloni, and the expression and location of embryo/larval hemoglobin genes at different stages of embryonic development was tested by using whole embryo in situ hybridization. The members of the embryo/larval hemoglobin gene family were identified based on the genome data of G. eckloni. Then the RNA probes were prepared according to the obtained CDS sequences. Finally, we used the whole embryo in situ hybridization to investigate the expression patterns of the embryo/larval hemoglobin gene of G. eckloni during early embryonic development. The results showed that there were five embryo/larval hemoglobin genes in G. eckloni genome, including hbae1, hbae4, hbae5, hbbe1and hbbe3. Compared to the zebrafish, the hbae3 and hbbe2 genes have lost in G. eckloni in the genome evolution, suggesting that the recent small-scale gene-deleted events after the latest WGD (4R) have played important roles in shaping the embryo/larval hemoglobin gene repertoire in G. eckloni. The results of the whole embryo in situ hybridization experiment showed that the hbae1 gene expressed at 120h and continued to 432h of embryonic development, while the hbbe1 gene expressed at 96h and continued to 432h. It was observed that the hbbe3 genexpressed at 120h and continued to 384h. The hybridization signal of hbae4 and hbae5 could not be observed in the whole process of embryo development. The hybrid signals were mainly located in the median axis of the embryo, the posterior lateral mesoderm, the ventral area of the dorsal aorta, the caudal hematopoietic tissue and the yolk sac. The sense probe was used as a negative control, the hybridization signal was not observed during embryonic development. Embryo/larval hemoglobin gene expression and localization studies showed that G. eckloni has unique characteristic of hemoglobin switching. Among them, hbae1, hbbe1 and hbbe3 played important roles in the embryo development of the G. eckloni, while the biological functions of hbae4 and hbae5 may be weakened.