The translation of an antiapoptotic protein HIAP2 is regulated by an upstream open reading frame

AbstractHIAP2 is a multifunctional protein that is critically involved in the regulation of cell survival and apoptosis. Here, we show that HIAP2 5′ untranslated region functions as a strong inhibitor of translation. Sequence analysis of human, mouse and rat sequences revealed that there exists a short open reading frame (ORF) that is located just upstream of the HIAP2 coding sequence. The translation of this uORF severely inhibited translation of the downstream reporter gene in vivo but not in vitro. Point mutation that destroys the CUG initiating codon of uORF markedly enhanced translation of the reporter gene without affecting the mRNA levels. Our results identify a novel translational regulatory mechanism that controls the expression of HIAP2 and point to the importance of tight regulation of antiapoptotic gene expression.

[1]  R. Korneluk,et al.  Distinct Regulation of Internal Ribosome Entry Site-mediated Translation following Cellular Stress Is Mediated by Apoptotic Fragments of eIF4G Translation Initiation Factor Family Members eIF4GI and p97/DAP5/NAT1* , 2003, The Journal of Biological Chemistry.

[2]  R. Korneluk,et al.  Genomic characterization of the mouse inhibitor of apoptosis protein 1 and 2 genes. , 1997, Genomics.

[3]  Masahiko Miura,et al.  Expression of cIAP1, a target for 11q22 amplification, correlates with resistance of cervical cancers to radiotherapy. , 2002, Cancer research.

[4]  A. Prats,et al.  Alternative Translation of the Proto-oncogene c-mycby an Internal Ribosome Entry Site* , 1997, The Journal of Biological Chemistry.

[5]  A. Prats,et al.  Alternative translation of human fibroblast growth factor 2 mRNA occurs by internal entry of ribosomes , 1995, Molecular and cellular biology.

[6]  C. Duckett,et al.  c-IAP1 Is Cleaved by Caspases to Produce a Proapoptotic C-terminal Fragment* , 2001, The Journal of Biological Chemistry.

[7]  M. Malim,et al.  Suppression of tumor necrosis factor-induced cell death by inhibitor of apoptosis c-IAP2 is under NF-kappaB control. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[8]  T. Chow,et al.  Translational upregulation of X-linked inhibitor of apoptosis (XIAP) increases resistance to radiation induced cell death , 2000, Oncogene.

[9]  Mike Rothe,et al.  The TNFR2-TRAF signaling complex contains two novel proteins related to baculoviral inhibitor of apoptosis proteins , 1995, Cell.

[10]  J. Silke,et al.  Caspase inhibitors , 1999, Cell Death and Differentiation.

[11]  Kevin E. Hicks,et al.  Cloning and characterization of the rat homologues of the Inhibitor of Apoptosis protein 1, 2, and 3 genes. , 2002, BMC Genomics.

[12]  R. Korneluk,et al.  Genomic organization and physical map of the human inhibitors of apoptosis: HIAP1 and HIAP2 , 1999, Mammalian Genome.

[13]  G. Salvesen,et al.  Apoptosis: IAP proteins: blocking the road to death's door , 2002, Nature Reviews Molecular Cell Biology.

[14]  J. Inazawa,et al.  Identification of cIAP1 as a candidate target gene within an amplicon at 11q22 in esophageal squamous cell carcinomas. , 2001, Cancer research.

[15]  R. Korneluk,et al.  XIAP, the guardian angel , 2001, Nature Reviews Molecular Cell Biology.

[16]  J C Reed,et al.  Dysregulation of apoptosis in cancer. , 1998, The cancer journal from Scientific American.

[17]  Yili Yang,et al.  TNF-RII and c-IAP1 mediate ubiquitination and degradation of TRAF2 , 2002, Nature.

[18]  John Calvin Reed,et al.  A cis-acting element in the BCL-2 gene controls expression through translational mechanisms. , 1996, Oncogene.

[19]  A. Geballe.  6 Translational Control Mediated by Upstream AUG Codons , 1996 .

[20]  J C Reed,et al.  Expression and prognostic significance of IAP-family genes in human cancers and myeloid leukemias. , 2000, Clinical cancer research : an official journal of the American Association for Cancer Research.

[21]  T. Chow,et al.  A new internal-ribosome-entry-site motif potentiates XIAP- mediated cytoprotection , 1999, Nature Cell Biology.

[22]  R. Korneluk,et al.  XIAP: Apoptotic brake and promising therapeutic target , 2001, Apoptosis.