Differential expression of speckled POZ protein, SPOP: putative regulation by miR-145.
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.
Department of Animal Science and 2Graduate Institute of Biotechnology, Chinese Culture University, Yang Ming Shan, Taipei, Taiwan 111.
Chiu-Jung
CJ
Huang
Hsing-Yu
HY
Chen
Wan-Yi
WY
Lin
Kong Bung
KB
Choo
D020413:3' Untranslated Regions; D000818:Animals; D001665:Binding Sites; D045744:Cell Line, Tumor; D005786:Gene Expression Regulation; D006801:Humans; D008297:Male; D051379:Mice; D035683:MicroRNAs / Q000378:metabolism / Q000502:physiology*; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011689:Purkinje Cells / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012671:Seminiferous Tubules / Q000378:metabolism; D043743:Ubiquitin-Protein Ligase Complexes; D054875:Ubiquitination
D020413:3' Untranslated Regions; C541010:MIRN145 microRNA, human; C543499:MIRN145a microRNA, mouse; D035683:MicroRNAs; D009687:Nuclear Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; C509761:SPOP protein, human; C509762:Spop protein, mouse; D043743:Ubiquitin-Protein Ligase Complexes