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Updated: Aug 7, 2026
Retroviral Transduction of T-cell Receptors in Mouse T-cells
Published on: October 22, 2010
Tissue-specific expression of human CD4 in transgenic mice
F P Gillespie1, L Doros, J Vitale
1TSI Corporation, Worcester, Massachusetts 01605.
Abstract:
The gene for the human CD4 glycoprotein, which serves as the receptor for human immunodeficiency virus type 1, along with approximately 23 kb of sequence upstream of the translational start site, was cloned. The ability of 5' flanking sequences to direct tissue-specific expression was tested in cell culture and in transgenic mice. A 5' flanking region of 6 kb was able to direct transcription of the CD4 gene in NIH 3T3 cells but did not result in detectable expression in the murine T-cell line EL4 or in four lines of transgenic mice. A larger 5' flanking region of approximately 23 kb directed high-level CD4 transcription in the murine T-cell line EL4 and in three independent lines of transgenic mice. Human CD4 expression in all tissues analyzed was tightly correlated with murine CD4 expression; the highest levels of human CD4 RNA expression were found in the thymus and spleen, with relatively low levels detected in other tissues. Expression of human CD4 protein in peripheral blood mononuclear cells was examined by flow cytometry in these transgenic animals and found to be restricted to the murine CD4+ subset of lymphocytes. Human CD4 protein, detected with an anti-human CD4 monoclonal antibody, was present on the surface of 45 to 50% of the peripheral blood mononuclear cells from all transgenic lines.
Insights
A 23 kb DNA sequence effectively drives human CD4 gene expression in mice, mirroring natural CD4 patterns. This finding is crucial for understanding HIV-1 receptor regulation and developing targeted therapies.
Area of Science:
- Molecular Biology
- Immunology
- Genetics
Background:
- The CD4 glycoprotein is essential as the primary receptor for the human immunodeficiency virus type 1 (HIV-1).
- Understanding the regulatory elements controlling CD4 gene expression is critical for insights into HIV-1 infection and potential therapeutic strategies.
Purpose of the Study:
- To identify and characterize the 5' flanking sequences of the human CD4 gene responsible for directing tissue-specific expression.
- To evaluate the functionality of these regulatory regions in both cell culture and transgenic mouse models.
Main Methods:
- Cloning of the human CD4 gene and approximately 23 kb of its upstream sequence.
- Testing the transcriptional activity of different 5' flanking regions (6 kb and 23 kb) in NIH 3T3 cells and the murine T-cell line EL4.
- Generating and analyzing transgenic mice to assess tissue-specific expression patterns of human CD4.
- Utilizing flow cytometry to examine human CD4 protein expression on peripheral blood mononuclear cells.
Main Results:
- A 6 kb 5' flanking region showed transcription in NIH 3T3 cells but lacked expression in EL4 cells and transgenic mice.
- A larger 23 kb 5' flanking region successfully directed high-level CD4 transcription in EL4 cells and three lines of transgenic mice.
- Human CD4 RNA expression in transgenic mice correlated with murine CD4 expression, with highest levels in the thymus and spleen.
- Human CD4 protein was detected on 45-50% of peripheral blood mononuclear cells, specifically on the CD4+ lymphocyte subset.
Conclusions:
- The approximately 23 kb 5' flanking region of the human CD4 gene contains crucial elements for directing appropriate tissue-specific and cell-type-specific expression.
- These findings provide valuable insights into the transcriptional regulation of the CD4 receptor, relevant for HIV-1 research and therapeutic development.
