Cloning and sequence analysis of rabbit progesterone-receptor complementary DNA

Area of Science:

• Molecular Biology
• Endocrinology
• Genetics

Background:

• The progesterone receptor (PR) plays a crucial role in reproductive physiology and is a member of the nuclear receptor superfamily.
• Understanding the molecular structure of PR is essential for elucidating its mechanism of action and its interactions with other signaling pathways.

Purpose of the Study:

• To isolate and characterize cDNA clones encoding the rabbit progesterone receptor.
• To determine the primary amino acid sequence and analyze the structural domains of the rabbit PR.
• To investigate the tissue-specific expression of PR mRNA.

Main Methods:

• Isolation of lambda gt11 cDNA clones using specific antibodies.
• RNA gel blot analysis to determine mRNA size and distribution.
• DNA sequencing to deduce the amino acid sequence.
• Comparative sequence analysis with other steroid receptors.

Main Results:

• Isolation of two lambda gt11 clones containing rabbit PR cDNA fragments.
• Identification of a 5900-nucleotide mRNA predominantly expressed in the uterus and vagina, with increased uterine levels after estrogen treatment.
• Deduction of a 930-amino acid PR sequence featuring a conserved DNA-binding domain and a variable N-terminal domain.
• Homology analysis revealed significant similarities in the cysteine-rich DNA-binding region and C-terminal domain with glucocorticoid and estrogen receptors, but divergence in the N-terminal region.

Conclusions:

• The study successfully elucidated the primary structure of the rabbit progesterone receptor.
• Structural comparisons highlight conserved and divergent regions among steroid receptors, providing insights into their functional specificity.
• The findings contribute to a deeper understanding of progesterone receptor function and its regulation in reproductive tissues.