Mutually Exclusive Neuronal Expression of Peptides Encoded By the FMRFa Gene Underlies a Differential Control of Copulation in Lymnaea

Abstract

An innovative method, direct peptide profiling of small samples of nervous tissue by matrix-assisted laser desorption ionization mass spectrometry, in combination with peptide characterization, immunocytochemistry in conjunction with specific neuronal labeling by backfilling of the penis nerve, and bioassay of peptides was used to study the intrinsic neuronal expression patterns of distinct sets of related FMRFa peptides and their significance for the organization of male copulation behavior in the mollusk, Lymnaea stagnalis. Previous studies indicate that the sets of FMRFa-related and GDPFLRFa-related peptides are encoded by two alternatively spliced transcripts of the single FMRFa gene. Direct mass spectrometry revealed that both FMRFa-related and GDPFLRFa-related peptides are present in the penis nerve, the sole nerve that innervates the penis complex. Accordingly, authentic FMRFa, GDPFLRFa, and related peptides were purified from the penis complex. The loci of synthesis of FMRFa and related peptides could be traced to the right cerebral ventral lobe, those of GDPFLRFa and related peptides to the B group neurons in the right parietal ganglion and to a few unidentified neurons in the right pleural ganglion. Notwithstanding their related structures, the two sets of peptides have distinctly different actions on the penis retractor muscle.

C2orf62 and TTC17 Are Involved in Actin Organization and Ciliogenesis in Zebrafish and Human

“…Peptides that disrupt interactions between R2D2 domains and AKAPs impair sperm motility [69], suggesting an important function for R2D2 domain-containing proteins in cilia or flagella function. This was recently confirmed for ROPN1 and ROPN1L [70] [71].We showed that mutations of Leu-318 and Phe-341, predicted to be required for dimerization and AKAP binding based on homology with other R2D2 domains [55] [67], prevented the developmental effects induced by the mRNA coding for the C-terminal part of zC2orf62. Therefore, a functional R2D2-like domain seems to be required for C2orf62 action on ciliogenesis in vivo, although we did not find any interaction between C2orf62 and an AKAP.…”

“…L13A and F36A mutations were shown to abolish PRKAR2B dimerization and binding to AKAP75 [55]. Because these residues are conserved in C2orf62 (Fig.…”

Neuro-endocrine control of reproduction in hermaphroditic freshwater snails: mechanisms and evolution

“…The different substances found in this lobe are summarized in Figure 1 and Table 1. FMRF is co-expressed with a number of the other peptides encoded on the same exon (Schott and Boer, 1982; Bright et al, 1993; Santama et al, 1993, 1995; Van Golen et al, 1995a; see Figure 1B). Furthermore, APGW, conopressin, LyNPY, and pedal peptide are all singly expressed in right ventral lobe neurons (Croll and Van Minnen, 1992; De Lange et al, 1997).…”

“…The penial complex – comprising the preputium, penis, and retractor muscles – is innervated by peptidergic neurons of the right anterior lobe, ventral lobe, pedal Ib cluster, and dispersed neurons from the right pleural and parietal ganglia (e.g., Kemenes et al, 1989; Croll et al, 1991; Li et al, 1992). For example, conopressin and APGW co-localize in neurons innervating the penial complex and vas deferens (Van Kesteren et al, 1992; Van Golen et al, 1995a,b). Fibers containing FMRF and its co-expressed peptides (see above and Table 1) are found in the penial complex (Bright et al, 1993; Santama et al, 1993, 1995; Van Golen et al, 1995a,b) as well as several other substances (see Table 2).…”

Egg-Laying in the Cuttlefish Sepia officinalis

“…These neuropeptides are widely distributed in the animal kingdom and involved in many physiological regulation processes in mollusks such as heart activity [28], amylase secretion [29], feeding [30], and reproduction [31]. In cuttlefish, they are believed to regulate egg capsule secretion and oocyte transport in the oviduct [3] and also chromatophore control pathways [32].…”