DNA sequence preference of the progesterone receptor

Area of Science:

• Molecular biology
• Genetics
• Biochemistry

Background:

• The progesterone receptor (PR) is a key regulator of gene expression in response to progesterone.
• Understanding PR binding to DNA is essential for elucidating gene regulation mechanisms.

Purpose of the Study:

• To investigate the DNA binding preferences of the highly purified hen oviduct progesterone receptor A subunit (PR-A).
• To identify specific DNA sequences and genomic regions that interact with PR-A.

Main Methods:

• Nitrocellulose filter adsorption assay using [32P]DNA fragments from recombinant plasmids.
• Testing binding to DNA fragments from chicken ovalbumin, gene Y, beta-globin, and alpha-actin genes.
• Restriction endonuclease mapping to localize binding sites.

Main Results:

• PR-A showed a marked preference for DNA fragments flanking the 5' end of steroid-regulated genes (ovalbumin and gene Y).
• No significant binding preference was observed for DNA fragments from chicken beta-globin and alpha-actin genes.
• Multiple PR-A interaction sites were identified upstream of the ovalbumin gene, with one located between -135 and -247 base pairs.
• This specific binding region contains an 18-base-pair A+T-rich sequence.

Conclusions:

• PR-A exhibits sequence-specific DNA binding preferences.
• The identified A+T-rich region upstream of the ovalbumin gene is a likely DNA binding site for PR-A.
• These findings contribute to understanding the molecular mechanisms of progesterone-mediated gene regulation.