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A single locus on human chromosome 21 directs the expression of a receptor for adenovirus type 2 in mouse A9 cells
1Biology Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
Abstract:
The receptors on human cells which mediate adsorption of adenoviruses have not been identified. We found that murine A9 cells and Chinese hamster ovary (CHO) cells failed to bind significant levels of radiolabeled adenovirus type 2 (Ad2) virions but that derivatives of these cells carrying human chromosome 21 exhibited high levels of virus binding that was specific for the viral fiber protein. G418-resistant A9 cell transformants expressing Ad2 receptors were detected at a frequency of about 10(-4) following cotransfection with high-molecular-weight DNAs from mouse cells containing human chromosome 21 and plasmid DNA containing a neomycin resistance gene. The Ad2 receptors on the transformed A9 cells were similar to those on human cells with respect to their concentration on the cell membrane, their affinity for the viral fiber protein, and their ability to direct virus into cells along a pathway leading to delivery of the viral DNA genome into the cell nucleus. Furthermore, identical human DNA fragments were present in three independent mouse cell transformants expressing Ad2 receptors, supporting the conclusion that these human DNA fragments correspond to a gene or locus on chromosome 21 that directs the expression of Ad2 receptors in these cells.
Insights
Researchers identified human chromosome 21 as crucial for adenovirus binding. This chromosome contains genes that code for adenovirus receptors, enabling virus entry into cells.
Area of Science:
- Virology
- Molecular Biology
- Genetics
Background:
- The specific receptors mediating adenovirus adsorption to human cells remain unidentified.
- Adenovirus infections pose significant health challenges, necessitating a deeper understanding of viral entry mechanisms.
Purpose of the Study:
- To identify the cellular receptors responsible for adenovirus type 2 (Ad2) binding.
- To investigate the role of human chromosome 21 in mediating Ad2 adsorption and entry.
Main Methods:
- Utilized murine A9 and Chinese hamster ovary (CHO) cells, including derivatives containing human chromosome 21.
- Employed radiolabeled Ad2 virions for binding assays.
- Performed G418 selection and DNA analysis to identify Ad2 receptor-expressing cell lines.
Main Results:
- Cells engineered to carry human chromosome 21 demonstrated significant, specific binding of Ad2 virions via the viral fiber protein.
- Transformed A9 cells expressing Ad2 receptors exhibited characteristics similar to human cells, including receptor concentration, affinity, and entry pathway.
- Identical human DNA fragments were consistently found in independent transformants, pinpointing a locus on chromosome 21 responsible for Ad2 receptor expression.
Conclusions:
- Human chromosome 21 harbors the gene(s) encoding the Ad2 receptor.
- This discovery provides critical insights into adenovirus cell entry and potential therapeutic targets.