Expression of Proopiomelanocortin and Its Cleavage Enzyme Genes in Rana esculenta and Xenopus laevis Gonads

Abstract

Proopiomelanocortin (POMC) is the precursor protein of different hormones and neuropeptides, and the POMC-derived peptides are produced through proteolytic cleavage. Prohormone convertase PC1 and PC2 are enzymes responsible for the cleavage of the POMC prohormone. The coexpression of POMC, PC1, and PC2 genes was previously described in the brain and the pituitary gland of Rana esculenta and Xenopus laevis, but no data are available for the gonad. The present work demonstrates a gonadal POMC convertase gene expression in Rana esculenta and Xenopus laevis.

Nociceptin/Orphanin FQ Peptide Receptors: Pharmacology and Clinical Implications

“…Following gene transcription, splicing and trimming of the message the translation process, which occurs on the ribosomes in the cell body of the peptidergic neuron, is initiated to form the prepropeptide. The prepropeptide consists of a single amino acid sequence of around 200 to 300 residues including a signal peptide in its N-terminal portion [10,11]. The signal peptide is involved in the process to translocate the prepropeptide after translation being completed.…”

“…The C-terminal portion of SP is known to interact with the NK-1 receptor and fragments containing this sequence can mimic many of the agonistic effects mediated through this receptor. Several bioactive C-terminal fragments of SP are formed through the actions of post-proline cleaving enzymes, such as DP-IV giving rise to SP (3)(4)(5)(6)(7)(8)(9)(10)(11) and SP(5-11), or postproline cleaving endopeptidase (PPCE) or prolyl endopeptidase [54]. These fragments have also been identified in various CNStissues [55].…”