Carboxy-terminal domain of AID required for its mRNA complex formation in vivo
| Autor: | Takae Toyoshima, Kazuo Kinoshita, Masamichi Muramatsu, Taichiro Nonaka, Tomomitsu Doi, Tasuku Honjo |
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| Rok vydání: | 2009 |
| Předmět: |
Messenger RNA
Multidisciplinary Base Sequence Polyadenylation biology Reverse Transcriptase Polymerase Chain Reaction APOBEC-1 Deaminase APOBEC1 RNA APOBEC-3G Deaminase Cytidine deaminase Biological Sciences Cell Line Biochemistry RNA editing Cytidine Deaminase Activation-induced (cytidine) deaminase biology.protein Humans RNA Editing RNA Messenger DNA Primers |
| Zdroj: | Proceedings of the National Academy of Sciences. 106:2747-2751 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.0812957106 |
| Popis: | Activation-induced cytidine deaminase (AID) is essential for the class switch recombination (CSR) and somatic hypermutation (SHM) of Ig genes. Originally, AID was postulated to be an RNA-editing enzyme, because of its structural homology with a known RNA-editing enzyme, APOBEC1. In support of this idea, AID shares many of the properties of RNA-editing enzymes, including nucleocytoplasmic shuttling and a dependency on de novo protein synthesis. However, it has not been shown whether AID recognizes a specific mRNA and edits it to generate an enzyme involved in CSR or SHM. Here, we examined the association between AID and polyadenylated [poly(A) + ] RNA in vivo, using UV cross-linking coupled with a poly(A) capture method that relies on biotinylated oligo(dT) and streptavidin-conjugated beads. We found that both exogenous AID expressed in transfected CH12 cells and endogenous AID expressed in BL2 cells were associated with poly(A) + RNA. Similar protein-poly(A) + RNA complexes were formed by APOBEC1 and APOBEC3G. However, the interactions of all of these cytidine deaminase family members, including AID, with poly(A) + RNA were indirect. This was expected for APOBEC1, which is known to act through an RNA-interacting cofactor, APOBEC1 complementation factor (ACF). In addition, the carboxy-terminal region of AID, which is essential for class switching, was also required for its interaction with poly(A) + RNA. These results suggest that the CSR activity of AID requires an ACF-like cofactor that specifically interacts with the carboxy-terminal domain of AID. |
| Databáze: | OpenAIRE |
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