RER, an evolutionarily conserved sequence upstream of the rhodopsin gene, has enhancer activity

Area of Science:

• Genetics
• Molecular Biology
• Neuroscience

Background:

• Mammalian rhodopsin gene promoter localization was previously studied.
• A conserved 100-bp sequence upstream of the rhodopsin gene was identified as a potential regulatory region.

Purpose of the Study:

• To investigate the enhancer activity of the conserved 100-bp sequence in vivo.
• To determine if this sequence influences rhodopsin gene expression.

Main Methods:

• Generation of transgenic mice with rhodopsin promoter/lacZ constructs, with and without the 100-bp sequence.
• Analysis of photoreceptor-specific transgene expression.
• Gel mobility shift and DNase I footprint assays using bovine retinal nuclear extracts.

Main Results:

• Transgenic mice with the 100-bp sequence exhibited significantly higher photoreceptor-specific transgene expression.
• The 100-bp sequence fused to a minimal heterologous promoter did not drive retinal expression independently.
• Retinal nuclear extracts showed sequence-specific binding of factors to the 100-bp region.

Conclusions:

• The 100-bp sequence functions as a rhodopsin enhancer in vivo.
• This enhancer region plays a crucial role in regulating rhodopsin gene expression in photoreceptors.