Expressional Analysis of Zebrafish Serbp1a and Serpine1

Purpose: SERBP1 (PAIRBP1) can bind to the serpine1 (pai-1) mRNA and has been correlated with tumor formation and progression. We thus used zebrafish as a model system to study the expression and function of serbp1a during embryogenesis.
Methods: Total RNA and proteins were prepared from zebrafish embryos for RT-PCR and Western blot analyses. Whole-mount in situ hybridization were conducted to detect the expression of serbp1a and serpine1 at different embryonic stages. Antisense morpholino oligonucleotides were injected to produce serbp1a knock-down morphants.
Results: Zebrafish serbp1a is expressed from zygotic to late developmental stages. Intense expression can be detected in somite at 24 hours post fertilization (hpf), brain boundary and pectoral fin bud at 48 hpf, along with liver and intestine at 72 hpf. The serbp1a morphants showe decreased Serbp1 expression, small brain, abnormal posterior trunk, and defective somite patterning. Co-injection with wildtype full-length RNA decreased the defect rate and death rate of the morphants extensively, indicating the specificity of the knockdown. We also showed the expression pattern of serpine1. Early ubiquitous expression before gastrulation and liver expression at 72 hpf are similar to that of serbp1a. However, the expression pattern and level of serpine1 were barely affected in the serbp1a morphants and in a human hepatoma cell line Huh7 with SERBP1 knockdown.
Conclusion: Based on our findings, serbp1a plays important roles during zebrafish embryonic development even though not through affecting serpine1.