Regional differences in processing of locally translated prohormone in peptidergic neurons of Aplysia californica

• Published in: Journal of neurochemistry 2002-12, Vol.83 (6), p.1423-1430
• Main Authors: Lee, Wenjau, Jones, Andrea M., Ono, Joyce K., Wayne, Nancy L.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Aplysia; Aplysia californica; bag cells; Base Sequence; Biochemistry. Physiology. Immunology; Biological and medical sciences; egg-laying hormone; Fundamental and applied biological sciences. Psychology; In Vitro Techniques; Invertebrate Hormones - genetics; Invertebrate Hormones - metabolism; Invertebrates; Marine; Molecular Sequence Data; Mollusca; mRNA; Nervous System - cytology; Nervous System - metabolism; neurite; Neurites - metabolism; neuroendocrine system; Neurons - metabolism; Neuropeptides - metabolism; Physiology. Development; post‐translational processing; protein processing; Protein Processing, Post-Translational - physiology; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - metabolism; Sequence Homology, Amino Acid
• ISSN: 0022-3042; 1471-4159
• DOI: 10.1046/j.1471-4159.2002.01252.x

Earlier work showed that cell bodies and neurites of the peptidergic bag cell neurons of Aplysia californica contain mRNA for egg‐laying hormone. The purpose of the present study was to determine if egg‐laying hormone synthesis and prohormone processing is similar in the pleurovisceral connective nerves (containing neurites of bag cell neurons) and the bag cell neuron clusters (containing both cell bodies and neurites of bag cell neurons). Initial experiments confirmed by RT‐PCR and sequencing that egg‐laying hormone mRNA was present in the pleurovisceral connective nerves. To investigate possible regional differences in translation of mRNA and prohormone processing, clusters were separated from connective nerves and newly synthesized egg‐laying hormone‐immunoreactive proteins were analyzed. Results showed that synthesis and processing of prohormone occurred in both the clusters and isolated connective nerves; however, the relative abundance of prohormone, processing intermediates, and egg‐laying hormone was different. Pulse‐chase experiments showed that prohormone was processed more slowly in the connective nerves than in the clusters. These results show that mRNA in isolated neural processes of neuroendocrine cells can be translated, and that the cellular machinery for protein synthesis is present, but processing of the ELH prohormone is significantly compromised.