The expression of human interferon alpha genes.

Area of Science:

• Immunology
• Molecular Biology
• Genetics

Background:

• Interferons (IFNs) are crucial cytokines involved in immune responses.
• Understanding the differential expression of IFN subtypes is vital for comprehending cellular defense mechanisms.

Purpose of the Study:

• To quantify and compare the mRNA levels of various IFN subtypes (IFN-beta, IFN-gamma, and multiple IFN-alpha subtypes) in normal and leukaemic human blood leucocytes.
• To investigate the impact of cell type and induction methods on IFN mRNA expression profiles.

Main Methods:

• Quantitative analysis of mRNA levels for IFN-beta, IFN-gamma, and specific IFN-alpha subtypes (1, 2, 4, 5, 6, 7, 8, 14).
• Comparison of transcript levels in normal leucocytes, leukaemic leucocytes, and induced cell lines.
• Analysis of the 5' flanking sequence of the human IFN-alpha 1 gene using reversed genetics.

Main Results:

• The ratio of IFN-alpha to IFN-beta transcripts varied significantly based on cell type.
• IFN-alpha 1, -alpha 2, and -alpha 4 were major IFN-alpha transcripts in normal leucocytes, while others were minor.
• A notable difference in individual IFN-alpha mRNA proportions was observed between normal and leukaemic cells, with high IFN-alpha 14 expression in myeloblastic leukaemia.
• Induction protocols did not substantially alter IFN mRNA proportions.

Conclusions:

• Cell type, particularly leukaemic transformation, profoundly influences the expression profile of IFN-alpha subtypes.
• Specific IFN-alpha subtypes exhibit distinct expression patterns in different cellular contexts.
• A key regulatory region in the 5' flanking sequence of the IFN-alpha 1 gene was identified for viral inducibility.