An amplification-promoting sequence from mouse genomic DNA: interaction with a trans-acting factor that also affects...

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• Murine DNA sequences capable of stimulating cis-linked plasmid DNA amplification in mouse cells were previously identified.
• This study focuses on the structural and functional characterization of a specific 229-bp element, designated element 5.

Purpose of the Study:

• To identify the amplification-promoting region within element 5.
• To elucidate the mechanism of action of element 5, including protein interactions and functional significance.
• To investigate potential links between DNA amplification and RNA polymerase II transcription.

Main Methods:

• Deletion analysis to pinpoint the active region of element 5.
• DNA footprinting assays to characterize protein-DNA interactions.
• Functional assays assessing amplification promotion and RNA polymerase II promoter activity.

Main Results:

• The amplification-promoting activity of element 5 resides in its middle portion.
• A specific DNA binding site within this region interacts with a nuclear protein.
• This binding site is crucial for amplification and also functions as a promoter element for RNA polymerase II transcription, notably enhancing a truncated herpes simplex virus type 1 thymidine kinase promoter.

Conclusions:

• Element 5 functions in a cis-acting manner through interaction with a trans-acting factor.
• The identified protein appears to play a dual role, participating in both DNA amplification and RNA polymerase II transcription.
• This suggests a potential mechanistic link between these two fundamental cellular processes.