The proto-oncogene JUN is a target of the heat shock transcription factor HSF1

Area of Science:

• Molecular Biology
• Cellular Stress Response

Background:

• The transcription factor activator protein-1 (AP-1) regulates key cellular processes.
• AP-1 is a dimeric complex mainly composed of Jun and Fos proteins.
• Heat shock transcription factor 1 (HSF1) controls the expression of molecular chaperones and is involved in stress response, aging, and carcinogenesis.

Purpose of the Study:

• To investigate the regulatory relationship between HSF1 and JUN, a component of AP-1.
• To elucidate the role of HSF1 in modulating AP-1 activity.

Main Methods:

• Analysis of JUN transcription in HeLa cells under heat treatment.
• Chromatin immunoprecipitation to assess HSF1 binding to the JUN promoter.
• Examination of c-Jun expression and activity following HSF1 modulation.

Main Results:

• JUN transcription is rapidly induced by heat shock in HeLa cells.
• HSF1 directly binds to the JUN promoter and is essential for heat-induced JUN expression.
• Forced expression of active HSF1 increases c-Jun levels and activates c-Jun target genes.

Conclusions:

• HSF1 acts as a regulator of JUN gene expression.
• HSF1 influences AP-1 activity by controlling JUN levels, particularly under heat stress conditions.