Abstract
Terminal deoxynucleotidyltransferase (TdT), which template-independently synthesizes DNA during V(D)J recombination in lymphoid cells, is ubiquitylated by a BPOZ-2/Cul3 complex, as the ubiquitin ligase, and then degraded by the 26 S proteasome. We show here that TdT is ubiquitylated by the Cul3-based ubiquitylation system in vitro. Because TdT could also be ubiquitylated in the absence of Cul/BPOZ-2, we determined that it could also be directly ubiquitylated by the E2 proteins UbcH5a/b/c and UbcH6, E3-independently. Furthermore, the ubiquitylated TdT inhibited its nucleotidyltransferase activity.
MeSH terms
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Animals
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Cattle
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Cullin Proteins / genetics
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Cullin Proteins / metabolism
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DNA Nucleotidylexotransferase / genetics
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DNA Nucleotidylexotransferase / metabolism*
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Feedback, Physiological*
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Gene Expression Regulation*
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Gene Library
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HeLa Cells
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Humans
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Liver / cytology
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Liver / metabolism
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Plasmids
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Proteasome Endopeptidase Complex / genetics
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Proteasome Endopeptidase Complex / metabolism
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Proteolysis
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Repressor Proteins / genetics
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Repressor Proteins / metabolism
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Thymus Gland / cytology
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Thymus Gland / metabolism
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Transfection
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Ubiquitin-Conjugating Enzymes / genetics
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Ubiquitin-Conjugating Enzymes / metabolism
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Ubiquitin-Protein Ligases / genetics
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Ubiquitin-Protein Ligases / metabolism
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Ubiquitination / genetics*
Substances
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ABTB1 protein, human
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CUL3 protein, human
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Cullin Proteins
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Repressor Proteins
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UBE2D1 protein, human
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UBE2D2 protein, human
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UBE2D3 protein, human
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Ubiquitin-Conjugating Enzymes
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Ubiquitin-Protein Ligases
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DNA Nucleotidylexotransferase
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Proteasome Endopeptidase Complex
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ATP dependent 26S protease