title: p73 expression is regulated by RNPC1, a target of the p53 family, via mRNA stability.
abstract: p73, a p53 family tumor suppressor, is expressed as TA and ΔN isoforms. Due to the role of p73 in tumor suppression and neural development, its expression and activity are tightly regulated by multiple mechanisms, including transcription and posttranslational modifications. Here, we found that p73 mRNA stability is regulated by RNPC1, an RNA binding protein and a target of the p53 family. We also showed that a CU-rich element in the 3' untranslated region of p73 is recognized by and responsive to RNPC1. To explore the physiological significance of RNPC1-regulated p73 expression, we showed that the loss of RNPC1 in p53-null mouse embryonic fibroblasts leads to reduced expression of p73, along with decreased expression of p21, p130, and γ-H2A.X, and consequently a decreased number of senescent cells. Furthermore, we observed that knockdown of TAp73 or p21, another target of RNPC1, attenuates the inhibitory effect of RNPC1 on cell proliferation and premature senescence, whereas combined knockdown of TAp73 and p21 completely abolishes it. Due to the fact that RNPC1 is a target of p73, the mutual regulation between p73 and RNPC1 constitutes a novel feed-forward loop, which might be explored as a target for tumors without a functional p53.
authors.affiliation: Comparative Oncology Laboratory, University of California at Davis, Davis, California, USA.
authors.forename: Wensheng
authors.initials: W
authors.lastname: Yan
authors.forename: Jin
authors.initials: J
authors.lastname: Zhang
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yong-Sam
authors.initials: YS
authors.lastname: Jung
authors.forename: Xinbin
authors.initials: X
authors.lastname: Chen
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D001483:Base Sequence; D059447:Cell Cycle Checkpoints; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002478:Cells, Cultured; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D055786:Gene Knockout Techniques; D016158:Genes, p53; D045325:HCT116 Cells; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D008954:Models, Biological; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D020871:RNA Stability; D034741:RNA, Small Interfering / Q000235:genetics; D016601:RNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000378:metabolism*
chemical_list: D020413:3' Untranslated Regions; D050759:Cyclin-Dependent Kinase Inhibitor p21; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C515435:RBM38 protein, human; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; C547649:Rbm38 protein, mouse; C495901:TP53 protein, human; C000606460:TP73 protein, human; C000606368:Trp73 protein, mouse; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins