Linked Life Data

9271626

Source:http://linkedlifedata.com/resource/pubmed/id/9271626

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1997-10-9
pubmed:databankReference
pubmed:abstractText
One component of antigen receptor diversity shared by all gnathostomes characterized to date is mediated by a unique DNA polymerase, terminal deoxynucleotidyl transferase (TdT), which generates significant functional diversity during immunoglobulin and T-cell receptor rearrangement. To gain further insight into the evolutionary origin(s) of this unique enzyme and the immune system, a thymic cDNA clone encoding TdT was isolated from rainbow trout. The 2.3 kilobase (kb) full-length clone contained an open reading frame of 1 506 base pairs with a deduced protein product of Mr 57 000. Sequence comparisons demonstrate that TdT has been highly conserved in both sequence (>70% aa similarity, >50 aa identity) and overall structure during the course of vertebrate evolution. An amino acid alignment of all known TdT sequences (chicken, Xenopus, mouse, human, cattle, and trout) reveals that some, but not all, structural motifs believed to be critical for TdT activity have been conserved. The TdT alignment, in conjuction with the recently solved crystal structure for rat beta-polymerase, supports the hypothesis that both may have evolved from a common ancestral repair gene. In addition, four PKC phosphorylation sites are conserved, and hence may be involved in TdT regulation. Because TdT contributes to the generation of junctional diversity in antigen receptors of immature lymphocytes, its expression serves as a developmental marker for the sites of teleost lymphopoiesis. Northern blot (2.3 kb message) analysis shows that TdT mRNA is highly expressed within the thymus and to a lesser extent in the pronephros. In addition, reverse transcriptase-polymerase chain reaction analysis detected transcipts of both RAG1 and TdT in the thymus, pronephros, mesonephros, spleen, and intestine, but not within muscle, liver, or brain. Finally, TdT cDNA was amplified from embryos at 20 days post-fertilization (pf), which correlates with the appearence of the thymus and pronephros anlage during trout ontogeny.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0093-7711
pubmed:author
pubmed:issnType
Print
pubmed:volume
46
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
367-75
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:9271626-Amino Acid Sequence, pubmed-meshheading:9271626-Animals, pubmed-meshheading:9271626-Base Sequence, pubmed-meshheading:9271626-Cloning, Molecular, pubmed-meshheading:9271626-DNA Nucleotidylexotransferase, pubmed-meshheading:9271626-DNA-Binding Proteins, pubmed-meshheading:9271626-Evolution, Molecular, pubmed-meshheading:9271626-Gene Expression, pubmed-meshheading:9271626-Gene Rearrangement, T-Lymphocyte, pubmed-meshheading:9271626-Hematopoietic Stem Cells, pubmed-meshheading:9271626-Homeodomain Proteins, pubmed-meshheading:9271626-Lymphocytes, pubmed-meshheading:9271626-Lymphoid Tissue, pubmed-meshheading:9271626-Molecular Sequence Data, pubmed-meshheading:9271626-Oncorhynchus mykiss, pubmed-meshheading:9271626-Receptors, Antigen, T-Cell, pubmed-meshheading:9271626-Sequence Analysis, DNA, pubmed-meshheading:9271626-Sequence Homology, Amino Acid
pubmed:year
1997
pubmed:articleTitle
Characterization of rainbow trout terminal deoxynucleotidyl transferase structure and expression. TdT and RAG1 co-expression define the trout primary lymphoid tissues.
pubmed:affiliation
The Basel Institute for Immunology, Grenzacherstrasse 487, CH-4005 Basel, Switzerland.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't