Expression of Vimentin Intermediate Filament for Vascular Development in Olive Flounder (Paralichthys olivaceus)

Abstract

Cardiovascular system is the primary organ to develop and reach a functional state, which underscores the essential role of the vasculature in the developing embryo. The vasculature is a highly specialized organ that functions in a number of key physiological works including the carrying of oxygen and nutrients to tissues. It is closely involved in the formation of heart, and hence it is essential for survival during the hatching period. The expression of genes involved during vascular development in the olive flounder (Paralichthys olivaceus) in the days after hatching is not fully understood. Therefore, we examined the expression patterns of genes activated during the development of flounder. Microscopic observations showed that formation of blood vessels is related to the expression of the vimentin gene. Also, the temporal expression patterns of this vimentin-like gene in the developmental stages and in the normal tissues of olive flounder. The purpose of this study was to examine the expression patterns of vimentin in normal tissues of the olive flounder and during the development of the vascular system in newly hatched olive flounders and HIF-1 plays a vital role in the formation of blood vessels during development. Vimentin expression was strong at the beginning of the development of blood vessels, and was present throughout all developmental stages. Our findings have important implications with respect to the roles of vimentin and HIF-1 in the development and evolution of the first blood vessels in olive flounder. Further studies are required to elucidate the vimentin-mediated hypoxic response signal transduction and to decipher the functional role of vimentin in developmental stages.

Keywords: Intermediate Filament (IF); Olive flounder.; Vascular development; Vimentin.

Fig. 1.

Development of blood vessel formation of the olive flounder (Paralichythys olivaceus). The experiment was fertilized eggs of olive flounder from the tank, oxygen supply and maintains a temperature of 20°C. (A) Schematic lateral view of the blood vessel and lymph node of a flat fish with key features labeled. (B) Photograph was shown during after hatching for 1 day, Magnification: ×300, ×500. The following structures can be identified in development olive flounder larvae under dissecting stereomicroscopes. Black arrows showed that blood vascular formation to larva stage in olive floubder. Scale bar, 300 μm.

Fig. 2.

The vimentin gene was deduced by amino acid alignment assay for the flounder. (A) The amino acid sequence alignment was deduced for the olive flounder vimentin gene. Vimentin sequences are aligned with the several spices. GenBank accession numbers of each species are as follows: Red seabream (Pagrus major) AAP20222.1, Tiger puffer (Takifugu rubripes) XP_003975498.1, Brichardi (Neolamprologus brichardi) XP_006792231.1, Nile tilapia (Oreochromis niloticus) XP_003438114.1, Cichlid (Pundamilia nyererei) XP_0057425 71.1, Zebra Mbuna (Maylandia zebra) XP_004542987.1. Clone Eyes1-A03 is indicated by Asterisk (*). It is indicates the invariant and conserved residues in Arrestin. The percentages in parentheses indicate the overall amino acid identities.

Fig. 3.

Expression of HIF-1 and vimentin gene induces in the early development. (A) The experiment was flounder fertilized eggs from the tank, oxygen supply and maintain a temperature of 20°C. Embryo and larva were harvested during hours post fertilization (HPF) and days after hatching (DAH) for the indicated periods. The RNA extracted and vimentin was analyzed by RT-PCR method. (B, C) The mRNA expression of perforin was analyzed by real-time PCR. Different letters over each bar with the standard deviation represent significant differrences one group according to unpaired matched comparisons (p < 0.05).

Fig. 4.

Expression of vimentin gene induces from several tissues in the olive flounder. Experiments are examined with various periods of adult fish. (A) Vimentin gene expression from the segmental tissue (B: brain, M: muscle, F: fin, E: eye, L: liver, S: spleen, K: kidney, G: gill) for the olive flounder by using RT-PCR analysis. (B) The mRNA expression of vimentin was analyzed by real-time PCR. Different letters over each bar with the standard deviation represent significant differences one group according to unpaired matched comparisons (p < 0.05).