The two isoforms of mouse terminal deoxynucleotidyl transferase differ in both the ability to add N regions and subcellular localization
| Autor: | François Rougeon, M Fanton d'Andon, Noëlle Doyen, O. Martinez, Quang Tri Nguyen, Laurent A. Bentolila |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Gene isoform
Molecular Sequence Data Thymus Gland Biology Transfection Polymerase Chain Reaction Isozyme General Biochemistry Genetics and Molecular Biology Cell Line Mice Bone Marrow DNA Nucleotidylexotransferase Chlorocebus aethiops Animals RNA Messenger Molecular Biology Cellular localization DNA Primers chemistry.chemical_classification B-Lymphocytes Base Sequence General Immunology and Microbiology General Neuroscience Hematopoietic Stem Cells Subcellular localization Molecular biology Recombinant Proteins Amino acid Isoenzymes Alternative Splicing Kinetics chemistry Terminal deoxynucleotidyl transferase Cytoplasm Nuclear localization sequence Research Article Subcellular Fractions |
| Zdroj: | The EMBO Journal. 14:4221-4229 |
| ISSN: | 0261-4189 |
| Popis: | Two alternatively spliced terminal deoxynucleotidyl transferase transcripts, TdTS and TdTL which code respectively for proteins of 509 and 529 amino acids have been previously identified in the mouse thymus. Here we show that the same two transcripts are also present in B lineage cells from bone marrow. In addition we demonstrate that the corresponding 20 amino acid insertion found near the carboxy-terminal end of TdTL significantly alters the function of the enzyme. In contrast to TdTS, TdTL does not catalyse N region insertions at the recombination junction of a V(D)J site-specific recombination substrate. In an attempt to explain the lack of N region insertions we have characterized the different parameters which distinguish the two isoforms of TdT. Examination of transfected cell extracts revealed a reduced capacity of TdTL to add nucleotides to the 3' end of DNA, consistent with a lower terminal transferase activity. Furthermore, the half-life of the TdTL protein in these cells is 2-fold shorter than that of TdTS. Finally, despite the fact that TdTL has the same nuclear localization signal as TdTS, the cellular localization of the two isoforms was strikingly different. In contrast to nuclear TdTS, TdTL was found exclusively in the cytoplasm. All these characteristics could contribute to the functional difference between the two isoforms of TdT. However, the subcellular localization of TdTL on its own can account for its inability to add N regions. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|