Gene dosage and down-regulation of the α-interferon receptor

Abstract

The gene coding for the α,β-interferon (α,β-IFN) receptor is localized to chromosome 21. Cells from patients with Down's syndrome (trisomy 21) contain an extra chromosome 21, which results in a 1.5 times increase of dosage for the genes localized to this chromosome. Trisomy 21 cells express more cell-surface α-IFN receptors, consistent with the increased gene dosage. Down-regulation of the α-IFN receptors in trisomy 21 and normal cells was studied by incubating the cells with α-IFN. The α-IFN-induced effects showed 1.6 times more internalized cell-surface α-IFN receptors in trisomy 21 cells compared with normal cells, but no statistically significant change in the dissociation constants. A close relationship was found between the α-IFN receptor number and the biological response expressed as 2′,5′-oligoadenylate synthetase activity.

Key Words:

• α-interferon receptor
• down-regulation
• Down's syndrome
• gene dosage
• 2′,5′-oligodenylate synthetase