Identification of specific mRNAs affected by treatments producing long-term facilitation in Aplysia.

Abstract

Neural correlates of long-term sensitization of defensive withdrawal reflexes in Aplysia occur in sensory neurons in the pleural ganglia and can be mimicked by exposure of these neurons to serotonin (5-HT). Studies using inhibitors indicate that transcription is necessary for production of long-term facilitation by 5-HT. Several mRNAs that change in response to 5-HT have been identified, but the molecular events responsible for long-term facilitation have not yet been fully described. To detect additional changes in mRNAs, we investigated the effects of 5-HT (1.5 hr) on levels of mRNA in pleural-pedal ganglia using in vitro translation. Four mRNAs were affected by 5-HT, three of which were identified as calmodulin (CaM), phosphoglycerate kinase (PGK), and a novel gene product (protein 3). Using RNase protection assays, we found that 5-HT increased all three mRNAs in the pleural sensory neurons. CaM and protein 3 mRNAs were also increased in the sensory neurons 4Corresponding author.by sensitization training. Furthermore, stimulation of peripheral nerves of pleural-pedal ganglia, an in vitro analog of sensitization training, increased the incorporation of labeled amino acids into CaM, PGK, and protein 3. These results indicate that increases in CaM, PGK, and protein 3 are part of the early response of sensory neurons to stimuli that produce long-term facilitation, and that CaM and protein 3 could have a role in the generation of long-term sensitization.

Characterization of the rapid transcriptional response to long-term sensitization training in Aplysia californica

“…In addition, we did not replicate previous findings (Zwartjes et al, 1998) of up-regulation of a reductase-related protein (MFC = 1.02) nor ApCalmodulin (MFC = 1.08). This is not surprising, however, as we analyzed a different timepoint (immediate in prior work versus 1 hour after training in this study) and a different tissue (sensory neurons only in prior work versus entire pleural ganglia in this study).…”

“…Previous research has shown that long-term sensitization training produces a rapid (within 1 hour) increase in the expression of six different transcripts in the pleural ganglia: ApC/EBP (GenBank: U00994; Alberini, Ghirardi, Metz, & Kandel, 1994), ApCREB1 (GenBank: NM_001256437; Bartsch, Casadio, Karl, Serodio, & Kandel, 1998), ApEgr (GenBank: KC608221; Cyriac et al, 2013), ApTBL-1 (GenBank: U57369; Liu et al, 1997), ApCalmodulin (GenBank: NM_001204580; Zwartjes et al, 1998), and an reductase-related protein (GenBank: NM_001204605; Zwartjes et al, 1998). To date, however, there have been no comprehensive efforts to characterize the rapid transcriptional response to long-term sensitization training (though see Castellucci, Kennedy, Kandel, & Goelet, 1988; Liu et al, 1997).…”

Memory formation and the regulation of gene expression

“…Inhibiting the expression of either protein was sufficient to block induction of long-term but not short-term facilitation. mRNAs for calmodulin and an as yet unidentified protein were also transiently increased immediately after sensitization training [107]. Three hours after the onset of long-term facilitation increases in the mRNA for the Aplysia homolog of BiP, an endoplasmatic reticulum resident protein with chaperone function, could be detected [108].…”

Poly-(ADP-Ribose) Polymerase-1 Is Necessary for Long-Term Facilitation inAplysia

“…In Aplysia, regulating the transcription of several genes is essential for LTF (Noel et al, 1993(Noel et al, , 1994Alberini et al, 1994;Hegde et al, 1997;Zwartjes et al, 1998;Bartsch et al, 2000;Giustetto et al, 2003). Chromatin remodeling plays a crucial role in regulating the expression of ApC/EBP (Guan et al, 2002).…”