Spatio-temporal Expression Of Diacylglycerol Kinase γ And ζduring Rat Embryogenesis

Objective:To explore the spatio-temporal expression pattern of diacylglycerol kinase y (DGKy) and diacylglycerol kinase ζ (DGKζ during rat embryogenesis by detecting the expression of DGKy and DGKζ at mRNA and protein level.Methods:(1) Whole mount in situ hybridization (WMISH) was carried out by using digoxigenin-labeled oligonucleotide probes for detecting the spatio-temporal expression patterns of DGKγ and ζ mRNA in E8.5-E12.5rat embryos.(2) Immunohistochemistry technique was used to detect the expression of DGK.y and ζ protein in nervous system of E12.5-E18.5rat embryos.Results:(1) Outcome of WMISHDGKy mRNA was expressed in anterior neuropore, posterior neuropore and caudal neural tube of E10.5embryos. At E11.5, DGKy mRNA was expressed in telencephalon and mesencephalon vesicles, maxillary prominence and forelimb bud. By E12.5, DGKy mRNA was mainly expressed in brain vesicles.DGKζ mRNA positive signal was observed in ectoderm of E8.5rat embryos. At E9.5, DGKζ mRNA was expressed in primitive groove. The expression pattern then changed to anterior neuropore and caudal neural tube at E10.5. At E11.5, DGKζ mRNA expression pattern was similar to DGKy mRNA except forelimb bud. By E12.5, DGKζ mRNA expression was also observed in dorsal root ganglion (DRG) and trigeminal ganglion.Cryosections that followed WMISH was made to show the inner positive signal: Both DGKγy and DGKζ mRNA were expressed in neuroepithelium, but DGKy mRNA in the whole layer and DGKζ mRNA in the apical surface.(2) Results of immunohistochemistryAt E12.5, DGKy protein was expressed in DRG and neuroepithelium of brain and spinal cord, especially in floor plate. At E13.5to14.5, DGKy was strongly expressed in floor plate, DRG and trigeminal ganglion, while weakly expressed in brain and spinal cord. At E15.5-18.5, the increased expression of DGKy was observed in the anterior horn of spinal cord and DRG.The expression pattern of DGKζ was similar to DGKy at E12.5to18.5. But DGKζ was expressed weakly in the anterior horn of spinal cord and DRG at E18.5.Conclusion:1. The expression of DGKζ mRNA in ectoderm and primitive streak suggests that DGKζ might take part in the formation of three germ layers.2. DGKy mRNA was expressed in anterior neuropore, posterior neuropore and DGKζ mRNA was expressed in anterior neuropore. These results suggest that both DGKγ and ζ might play a role in neuropore closure.3. The expression changes of DGKγ and ζ in brain, spinal cord and DRG reveal that they have a close relation with the early development of nervous system organs.