Linked Life Data

14500656

Source:http://linkedlifedata.com/resource/pubmed/id/14500656

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
2003-9-22
pubmed:abstractText
During thymic T cell development, immature CD4(+)/CD8(+) thymocytes develop into either CD4(+)/CD8(-) helper or CD4(-)/CD8(+) CTLs. The molecular mechanisms governing the complex selection and differentiation steps during thymic T cell development are not well understood. Here we developed a novel approach to investigate gene function during thymocyte development. We transfected ex vivo isolated immature thymocytes with gene-specific morpholino antisense oligonucleotides and induced differentiation in cell or organ cultures. A morpholino oligonucleotide specific for CD8alpha strongly reduces CD8 expression. To our knowledge, this is the first demonstrated gene knockdown by morpholino oligonucleotides in primary lymphocytes. Using this approach, we show here that the transcription factor Runx3 is involved in silencing of CD4 expression during CD8 T cell differentiation. Runx3 protein expression appears late in thymocyte differentiation and is confined to mature CD8 single-positive thymocytes, whereas Runx3 mRNA is transcribed in mature CD4 and CD8 thymocytes. Therefore, Runx3 protein expression is regulated at a post-transcriptional level. The knockdown of Runx3 protein expression through morpholino oligonucleotides inhibited the development of CD4(-)/CD8(+) T cells. Instead, mature cells with a CD4(+)/CD8(+) phenotype accumulated. Potential Runx binding sites were identified in the CD4 gene silencer element, which are bound by Runx protein in EMSAs. Mutagenesis of potential Runx binding sites in the CD4 gene silencer abolished silencing activity in a reporter gene assay, indicating that Runx3 is involved in CD4 gene silencing. The experimental approach developed here should be valuable for the functional analysis of other candidate genes in T cell differentiation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0022-1767
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
171
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3594-604
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:14500656-Amino Acid Sequence, pubmed-meshheading:14500656-Animals, pubmed-meshheading:14500656-Antigens, CD4, pubmed-meshheading:14500656-Base Sequence, pubmed-meshheading:14500656-Binding Sites, pubmed-meshheading:14500656-CD8-Positive T-Lymphocytes, pubmed-meshheading:14500656-Cell Differentiation, pubmed-meshheading:14500656-Cell Line, Tumor, pubmed-meshheading:14500656-Cells, Cultured, pubmed-meshheading:14500656-Core Binding Factor Alpha 3 Subunit, pubmed-meshheading:14500656-DNA-Binding Proteins, pubmed-meshheading:14500656-Down-Regulation, pubmed-meshheading:14500656-Gene Expression Regulation, pubmed-meshheading:14500656-Gene Silencing, pubmed-meshheading:14500656-Interleukin-7, pubmed-meshheading:14500656-Mice, pubmed-meshheading:14500656-Mice, Inbred C57BL, pubmed-meshheading:14500656-Molecular Sequence Data, pubmed-meshheading:14500656-Morpholines, pubmed-meshheading:14500656-Oligodeoxyribonucleotides, Antisense, pubmed-meshheading:14500656-Organ Culture Techniques, pubmed-meshheading:14500656-T-Lymphocyte Subsets, pubmed-meshheading:14500656-Thymus Gland, pubmed-meshheading:14500656-Transcription Factors, pubmed-meshheading:14500656-Transfection
pubmed:year
2003
pubmed:articleTitle
Morpholino antisense oligonucleotide-mediated gene knockdown during thymocyte development reveals role for Runx3 transcription factor in CD4 silencing during development of CD4-/CD8+ thymocytes.
pubmed:affiliation
Hans Spemann Laboratories, Max Planck Institute of Immunology, Freiburg, Germany. marc.ehlers@uni-essen.de
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't