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Sequence of a cDNA encoding pancreatic preprosomatostatin-22
Summary
Researchers sequenced the channel catfish somatostatin precursor, revealing a 105-amino acid protein. This precursor, upon processing, yields a 22-amino acid hormone homologous to other somatostatins.
Area of Science:
- * Molecular Biology
- * Endocrinology
- * Comparative Genomics
Background:
- * Somatostatin is a peptide hormone regulating various physiological processes.
- * Understanding somatostatin precursors provides insights into hormone evolution and function.
Purpose of the Study:
- * To determine the nucleotide sequence of the channel catfish somatostatin precursor.
- * To characterize the structure and potential processing of catfish somatostatin.
Main Methods:
- * cDNA sequencing of mRNA from channel catfish (Ictalurus punctatus).
- * Hybridization selection of mRNA followed by in vitro translation.
- * Analysis of polypeptide synthesis using Na-DodSO4/polyacrylamide gel electrophoresis.
Main Results:
- * The channel catfish cDNA encodes a 105-amino acid somatostatin precursor (Mr, 11,500).
- * The precursor contains a signal peptide, a connecting sequence, and the somatostatin-22 hormone.
- * Somatostatin-22 shares 7 of 14 amino acids with somatostatin-14, including key residues.
Conclusions:
- * The nucleotide sequence provides the genetic blueprint for channel catfish somatostatin.
- * The identified precursor structure suggests conserved processing mechanisms for somatostatin.
- * This study contributes to understanding the evolution of somatostatin across species.