Differential expression of speckled POZ protein, SPOP: Putative regulation by miR-145
- 140 Downloads
The speckle POZ protein, SPOP, is an adaptor of the Cul3-based ubiquitination process, and has been implicated in the carcinogenesis process. Despite recent elucidation of biological functions, regulation of SPOP gene expression has not been reported. In this study, the mRNA levels of the mouse SPOP (mSPOP) gene were first shown to vary noticeably in different tissues. However, the SPOP protein was detected in high abundance only in Purkinje cells of the cerebellum and seminiferous tubule of the testis, echoing previous reports of involvement of ubiquitination in neuron cells and in spermatogenesis. In other mouse tissues and human cancer cell lines analysed, only low SPOP protein levels were detected. The 3′-untranslated regions of both the mSPOP and human SPOP transcripts harbor a conserved putative miR-145 binding site (BS). In some tissues and cell lines, miR-145 and SPOP protein levels were in an inverse relationship suggesting miR-145 regulation. Luciferase assays of deletion and point mutation constructs of the miR-145 BS, and miR-145 induction by serum starvation that resulted in reduced endogenous SPOP levels provided further evidence that miR-145 is likely involved in post-transcriptional regulation of SPOP expression in selected tissues, and possibly with the participation of other miRNA species.
KeywordsCerebellar Purkinje cells spermatogenesis SPOP miR-145 TD/POZ protein family testicular seminiferous tubule
pancreatic duodenal homeobox 1
PDX-1 C-terminus-interacting factor 1
phosphatidylinositol phosphate kinase IIβ
seven-in-absentia homolog 1A
speckled POZ protein
steroid receptor co-activator-3
tumour necrosis factor
TNF receptor-associated factor
ubiquitin-conjugating enzyme 2i
This work was supported in part by a grant (NSC-101-2313-B-034-003) from the National Science Council (Taiwan) to CJH, and by a University Tunku Abdul Rahman intramural grant 6200/C39 to KBC.
- Hernandez-Munoz I, Lund AH, van der Stoop P, Boutsma E, Muijrers I, Verhoeven E, Nusinow DA, Panning B, et al. 2005 Stable X chromosome inactivation involves the PRC1 Polycomb complex and requires histone MACROH2A1 and the CULLIN3/SPOP ubiquitin E3 ligase. Proc. Natl. Acad. Sci. USA 102 7635–7640PubMedCentralPubMedCrossRefGoogle Scholar