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Appropriate developmental expression of human CD8 beta in transgenic mice
L J Kieffer1, L Yan, J H Hanke
1Department of Laboratory Medicine, Yale University, New Haven, CT 06520-8035, USA.
Journal of Immunology (Baltimore, Md. : 1950)
|November 20, 1997
Summary
Researchers created transgenic mice to study human CD8 beta gene regulation. The 95-kb DNA fragment enabled correct developmental expression in T cells, identifying key regulatory sequences within the fragment.
Area of Science:
- Immunology
- Molecular Biology
- Genetics
Background:
- The CD8 glycoprotein exists as alpha beta heterodimers or alpha alpha homodimers on T cells and lymphocytes.
- CD8 homodimers are found on specific T cell subsets, including TCR gamma delta intestinal intraepithelial lymphocytes (IELs).
Purpose of the Study:
- To investigate the molecular mechanisms regulating human CD8 beta gene expression.
- To identify regulatory sequences responsible for tissue-specific and lineage-specific expression of CD8 beta.
Main Methods:
- Generation of transgenic mice carrying a 95-kb human genomic DNA fragment encoding the CD8 beta gene and upstream regulatory elements.
- Analysis of human CD8 beta expression patterns in thymocytes, mature T cells, and intestinal IELs of transgenic mice.
- Assessment of DNase I-hypersensitive sites in relation to CD8 beta expression in cell lines.
Main Results:
- Transgenic mice exhibited correct developmental expression of human CD8 beta on thymocytes and mature CD8+ T cells.
- Expression was observed on TCR alpha beta+ intestinal IELs but not on TCR gamma delta IELs.
- Variegated expression patterns in founder lines indicated site of integration effects, while sibling expression was consistent.
Conclusions:
- The 95-kb human genomic DNA fragment contains regulatory sequences sufficient for developmentally correct CD8 beta expression in T cells.
- CD8 lineage-specific regulatory elements are located within this 95-kb fragment.