Terminal deoxynucleotidyl transferase 3034920 189522272 2008-02-06T16:33:57Z Mikael Häggström 2615838 direction {{protein |Name=deoxynucleotidyltransferase, terminal |caption= |image= |width= |HGNCid=2983 |Symbol=DNTT |AltSymbols= |EntrezGene=1791 |OMIM=187410 |RefSeq=NM_004088 |UniProt=P04053 |PDB= |ECnumber=2.7.7.31 |Chromosome=10 |Arm=q |Band=23 |LocusSupplementaryData=-q24 }} '''Terminal Deoxynucleotidyl Transferase''', also known as '''TdT''' and '''terminal transferase''', is a specialized [[DNA polymerase]] expressed in immature, pre-B, pre-T [[lymphoid]] cells, and [[acute lymphoblastic leukemia]]/lymphoma cells. TdT adds N-nucleotides to the variable, diversity, and joining [[exon]]s during [[antibody gene recombination]]. TdT [[catalysis|catalyses]] the addition of [[nucleotide]]s to the [[DNA end|3' terminus]] of a [[DNA]] molecule. Unlike most DNA polymerases it does not require a template. The preferred substrate of this enzyme is a [[DNA end|3'-overhang]], but it can also add nucleotides to blunt or recessed 3' ends. [[Cobalt]] is a necessary [[cofactor]]. Terminal transferase has applications in [[molecular biology]]. It can be used in [[RACE]] to add nucleotides which can then be used as a template for a primer in subsequent [[PCR]]. It can also be used to add nucleotides labelled with [[radioactivity|radioactive]] [[isotope]]s. Also used in the immunofluorescence assay for the diagnosis of acute lymphoblastic leukemia. It is the main enzyme used in [[TUNEL assay]] ('''T'''erminal deoxynucleotidyl transferase d'''U'''TP '''N'''ick '''E'''nd '''L'''abeling) for the demonstration of [[apoptosis]]. == See also == *[[DNA]] *[[DNA polymerase]] ==External links== * {{MeshName|Terminal+Deoxyribonucleotidyltransferase}} {{transferase-stub}} {{Kinases}} [[de:Desoxyribonukleotidyltransferase]]