Alternative splicing generates multiple isoforms of a rabbit prostaglandin E2 receptor

Area of Science:

• Molecular Biology
• Pharmacology
• Genetics

Background:

• Prostaglandin E2 (PGE2) receptors are crucial for various physiological processes.
• Understanding the specific receptor subtypes and their distribution is key to elucidating PGE2's functions.

Purpose of the Study:

• To isolate and characterize cDNA clones for prostaglandin E2 receptors from rabbit kidney.
• To determine the gene structure and expression patterns of these receptors.
• To confirm the functional identity and tissue distribution of the identified receptor variants.

Main Methods:

• cDNA library screening
• Southern blot analysis
• Genomic clone sequencing
• Transient expression in COS1 cells
• Ribonuclease protection assays
• In situ hybridization

Main Results:

• Four homologous cDNA clones encoding related proteins with distinct COOH-terminal sequences were isolated.
• Southern blot and genomic analysis confirmed these variants arise from alternative splicing of a single gene.
• Transient expression confirmed a ligand binding profile consistent with the EP3 receptor subtype.
• The gene is highly expressed in kidney, adrenal, and stomach, with lower expression in other tissues.
• Kidney expression is concentrated in the outer medulla and cortex.

Conclusions:

• The identified cDNA clones represent alternatively spliced variants of a single EP3 receptor gene.
• These EP3 receptor isoforms are functionally active and exhibit specific tissue distribution.
• The findings support a role for these receptors in mediating renal, gastric, and adrenal functions of prostaglandins.