Cloning and sequence analysis of cDNA encoding urotensin I precursor.

Area of Science:

• Neuroendocrinology
• Molecular Biology
• Evolutionary Biology

Background:

• Urotensin I is a neuropeptide hormone synthesized in the caudal neurosecretory system of fish.
• Understanding the structure and origin of neuropeptides is crucial for comparative endocrinology.

Purpose of the Study:

• To determine the primary structure of the urotensin I precursor in carp (Cyprinus carpio).
• To investigate the evolutionary relationship between urotensin I and related mammalian peptides.
• To identify the specific location of urotensin I precursor mRNA expression in carp.

Main Methods:

• Analysis of the nucleotide sequence of cloned complementary DNA (cDNA) encoding the urotensin I precursor.
• RNA transfer blot analysis to detect mRNA expression in various carp tissues.

Main Results:

• The carp urotensin I precursor comprises 145 amino acid residues.
• The mature urotensin I sequence (41 amino acids) is located at the carboxyl terminus, flanked by Lys-Arg and Gly-Lys.
• Sequence homology suggests an evolutionary relationship between carp urotensin I and mammalian corticotropin-releasing factors (CRFs).
• mRNA encoding the urotensin I precursor was exclusively detected in the carp spinal cord.

Conclusions:

• The primary structure of the carp urotensin I precursor has been elucidated.
• Carp urotensin I and mammalian CRFs likely share a common evolutionary origin.
• Urotensin I precursor gene expression is localized to the spinal cord in carp.