The mouse transketolase (TKT) gene: cloning, characterization, and functional promoter analysis

Area of Science:

• Molecular Biology
• Genetics
• Ophthalmology

Background:

• The transketolase (TKT) gene exhibits exceptionally high expression in the mature mouse cornea compared to other tissues.
• Understanding the regulation of TKT is crucial for comprehending corneal biology and potential disease mechanisms.

Purpose of the Study:

• To clone and characterize the mouse TKT gene and its regulatory elements.
• To investigate the transcriptional regulation of TKT, particularly in the cornea.
• To explore the role of oxidative stress in TKT gene expression.

Main Methods:

• Gene cloning and sequencing
• 5' RACE and primer extension assays to identify transcription start sites
• Reporter gene assays (CAT gene) in cell lines
• Analysis of TKT mRNA levels in vivo and in vitro under various conditions (e.g., oxidative stress).

Main Results:

• The mouse TKT gene was cloned and characterized, revealing its single-copy nature and evolutionary relationship to TKT-like genes.
• Two distinct transcription initiation sites were identified, with a TATA-less, GC-rich promoter utilized in the cornea.
• TKT mRNA levels significantly increased in the cornea post-eye opening and in response to oxidative stress inducers.
• Evidence suggests the presence of stress-inducible control sequences within the TKT promoter.

Conclusions:

• The TKT gene possesses unique promoter features adapted for high expression in the cornea.
• Oxidative stress appears to be a significant regulator of TKT gene expression in ocular tissues.
• These findings provide insights into the molecular mechanisms underlying corneal gene regulation and response to environmental stress.