| Summary: | 碩士 === 國立陽明大學 === 醫學生物技術暨檢驗學系暨研究所 === 99 === SPOP, speckle-type POZ protein, is a TD- and POZ-domain protein and a member of the TD/POZ protein family. SPOP is highly conserved in mammals and is ubiquitously expressed in human tissues. SPOP protein has been shown to participate in protein ubiquitination and degradation. To date, regulation of SPOP expression has not been studied. This study aimed to investigate the expression profiles of SPOP in human and mouse tissues. Possible microRNA regulation of SPOP expression was also studied.
Real-time RT-PCR and western blot were performed to determine mouse SPOP (mSPOP) mRNA and protein expression levels in mouse tissues and cell lines. The mRNA and protein levels of mSPOP were largely different in the tissues. mSPOP mRNA and protein had a very high level of expression in the brain. On the other hand, mSPOP mRNA was expressed in kidney and liver, but the protein was almost no detectable in these organs. To determine possible causes of mSPOP differential expression in these tissues, bioinformatics was used to analyze regulation of mSPOP by microRNA (miRNA). The results showed that mmu-miR-145 might regulate mSPOP expression. Real-time RT-PCR was performed to determine mmu-miR-145 expression levels. mmu-miR-145 and mSPOP protein expression showed significant inverse correlation in the organs. For example, the kidney showed significantly mmu-miR-145 expression level but the mSPOP protein level was very weak. In addition to analysis of the relationship between SPOP and miR-145 in mouse tissues, we also investigated human SPOP (hSPOP) expression in eight different human cancer cell lines. As similar with mouse tissues, hSPOP mRNA and protein levels were closely related with hsa-miR-145 expression in human cancer cell lines. We further over-expressed hsa-miR-145 in cell line HCT116 and observed significant decreased of the protein level of hSPOP.
Taken together, the results show differential expression of SPOP in mouse and human tissues and cell lines, and that hSPOP protein levels may be regulated by miR-145 at post-transcription levels. Further studies of regulation by other miRNA regulation in SPOP expression and the biological effects of differential SPOP in different tissues are in progress in our laboratory.
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