Apo B mRNA editing is an exquisitely site specific RNA modification that results in C to U deaminaton of a single cytidine base and creates a translational stop codon. This process occurs in the mammalian small intestine and is mediated by a multicomponent enzyme complex containing apobec-1, as well as other protein components of unknown identity. Apobec-1 is an RNA binding protein with specificity for AU-rich RNAs. Furthermore, RNA binding activity of apobec-1 is required for C to U editing of apo B mRNA. Progress over the last period has led to the identification of a high affinity binding site [UUUN(A/U)U] present in a single copy in apo B RNA close to the edited base. This motif is present in the 3' untranslated region (UTR) of a number of oncogenes, including c-myc, and cytokine mRNAs, including TNFa, IL-2 and GM-CSF. Each of these mRNAs contain AU-rich elements, which are known to be key mediators of mRNA stability. Apobec-1 binds to these RNAs in vitro and in vivo, an effect associated with increased stability of c-myc mRNA. These data suggest that apobec-1 may regulate the expression of genes other than apo B. We have further established that apobec-1 mediates C to U editing of NF1 mRNA, encoding the tumor suppressor, neurofibromin. Like apo B, NF1 RNA contains the consensus binding site in proximity to the edited C. C to U editing of NF1 mRNA, as in apo B mRNA, creates a translational stop codon and causes truncation of the protein. These findings serve as background for an examination of the mechanisms and requirements for apobec-1 mediated RNA binding and also for C to U editing of mRNAs, beyond apo B. Apobec-1 is required for C to U editing of apo B, but alone is insufficient, there being other proteins required. The number and identity of these factors is unknown. We have used a two-hybrid screen to clone a candidate factor, p54, whose interactions, distribution and function make it a candidate apo B RNA editing associated protein. We will examine the question of what additional proteins are required for the assembly and function of the apo B RNA editing enzyme, starting with a detailed characterization of p54. Finally, we have identified multiple apobec-1 related pjoteins (ARPs) in the human genome, using the signature sequence of apobec-1 flanking the catalytic site. One of these proteins, ARP-1 contains ~40% homology to apobec-1 and demonstrates cytidine deaminase and apo B RNA binding activity. We will examine the hypothesis in the current application that there are other cytidine deaminases, related to apobec-1, with functions involving site-specific RNA interactions.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37HL038180-23
Application #
7460553
Study Section
Special Emphasis Panel (NSS)
Program Officer
Rosenberg, Yves
Project Start
1986-07-01
Project End
2010-06-30
Budget Start
2008-07-01
Budget End
2009-06-30
Support Year
23
Fiscal Year
2008
Total Cost
$545,246
Indirect Cost
Name
Washington University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Lin, Jianguo; Zheng, Shizhong; Attie, Alan D et al. (2018) Perilipin 5 and liver fatty acid binding protein function to restore quiescence in mouse hepatic stellate cells. J Lipid Res 59:416-428
Willet, Spencer G; Lewis, Mark A; Miao, Zhi-Feng et al. (2018) Regenerative proliferation of differentiated cells by mTORC1-dependent paligenosis. EMBO J 37:
Eberth, Jan M; Josey, Michele J; Mobley, Lee R et al. (2018) Who Performs Colonoscopy? Workforce Trends Over Space and Time. J Rural Health 34:138-147
Wen, Yahong; Liao, Grace; Pritchard, Thomas et al. (2017) A stable but reversible integrated surrogate reporter for assaying CRISPR/Cas9-stimulated homology-directed repair. J Biol Chem 292:6148-6162
Newberry, Elizabeth P; Xie, Yan; Kennedy, Susan M et al. (2017) Prevention of hepatic fibrosis with liver microsomal triglyceride transfer protein deletion in liver fatty acid binding protein null mice. Hepatology 65:836-852
Lo, Hei-Yong G; Jin, Ramon U; Sibbel, Greg et al. (2017) A single transcription factor is sufficient to induce and maintain secretory cell architecture. Genes Dev 31:154-171
Ratnapradipa, Kendra L; Lian, Min; Jeffe, Donna B et al. (2017) Patient, Hospital, and Geographic Disparities in Laparoscopic Surgery Use Among Surveillance, Epidemiology, and End Results-Medicare Patients With Colon Cancer. Dis Colon Rectum 60:905-913
Cifarelli, Vincenza; Ivanov, Stoyan; Xie, Yan et al. (2017) CD36 deficiency impairs the small intestinal barrier and induces subclinical inflammation in mice. Cell Mol Gastroenterol Hepatol 3:82-98
Xie, Yan; Cifarelli, Vincenza; Pietka, Terri et al. (2017) Cd36 knockout mice are protected against lithogenic diet-induced gallstones. J Lipid Res 58:1692-1701
Nalbantoglu, ILKe; Blanc, Valerie; Davidson, Nicholas O (2016) Characterization of Colorectal Cancer Development in Apc (min/+) Mice. Methods Mol Biol 1422:309-27

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