Ultraviolet radiation increases HIV-long terminal repeat-directed expression in transgenic mice

Area of Science:

• Molecular Biology
• Virology
• Genetics

Background:

• The human immunodeficiency virus (HIV) long terminal repeat (LTR) is a key regulatory element controlling viral gene expression.
• Understanding factors that modulate HIV-LTR activity is crucial for developing therapeutic strategies.

Purpose of the Study:

• To investigate the effect of ultraviolet (UV) radiation on HIV-LTR-directed gene expression in vivo.
• To compare the efficacy of UV-C and UV-B radiation in inducing HIV-LTR expression.

Main Methods:

• FVB/N mice carrying an HIV-LTR/chloramphenicol acetyl transferase (CAT) transgene were exposed to UV-C (254 nm) or UV-B (312 nm) radiation.
• CAT gene expression levels were measured in ear and skin tissues at various time points post-exposure.

Main Results:

• UV-C exposure resulted in a 20-fold increase in HIV-LTR expression in ear tissue, while UV-B induced a fourfold increase.
• UV-C induction peaked on Day 3 (over 30-fold), and UV-B induction peaked on Day 5 (fivefold).
• CAT activity was not induced in fur-bearing skin but increased fourfold in shaved skin after UV-B treatment.

Conclusions:

• UV radiation, particularly UV-C, can significantly activate HIV-LTR-directed gene expression in mice.
• The presence of fur inhibits UV-induced gene expression, suggesting skin barrier properties influence activation.
• These findings may have implications for understanding viral reactivation and developing targeted therapies.