Gene structure and genetic localization of the PCLO gene encoding the presynaptic active zone protein Piccolo

Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294-0021, USA.
International Journal of Developmental Neuroscience (Impact Factor: 2.58). 06/2002; 20(3-5):161-71. DOI: 10.1016/S0736-5748(02)00046-1
Source: PubMed


Piccolo belongs to a family of presynaptic cytoskeletal proteins likely to be involved in the assembly and function of presynaptic active zones as sites of neurotransmitter release. Given that abnormalities in the formation of synaptic junctions are thought to contribute to cognitive dysfunction during brain development, we have analyzed and compared the gene structure of the Piccolo gene, PCLO, from humans and mice and determined their chromosomal localization. A comparison of the deduced amino acid sequence of cDNA clones encoding Piccolo from human, mouse, rat and chicken reveals the presence of distinct homology domains. Only subsets of these are also present in the structurally related active zone protein Bassoon indicating that Piccolo and Bassoon perform related but distinct functions at active zones. Characterization of the PCLO gene reveals the presence of 25 coding exons spread over 380kb of genomic DNA. The human PCLO gene maps to 7q11.23-q21.3, a region of chromosome 7 implicated as a linkage site for autism and Williams Syndrome suggesting that alterations in the expression of Piccolo or the PCLO gene could contribute to developmental disabilities and mental retardation.

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Available from: Steven D Fenster,
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    • "For Piccolino down regulation in rod photoreceptors, we used an shRNA, which was previously shown to successfully down regulate all Piccolo isoforms in cultured hippocampal neurons when introduced via lentiviral transduction (Pclo28; Leal-Ortiz et al., 2008; Waites et al., 2011). The target sequence for Pclo28 is located in Exon 1 of Piccolo, which encodes segments of the full-length Piccolo as well as the C-terminally truncated, ribbon synapse specific Piccolino (Figure 1A; Fenster and Garner, 2002; Regus-Leidig et al., 2013). To interfere with Piccolo/Piccolino "
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    ABSTRACT: Piccolo is the largest known cytomatrix protein at active zones of chemical synapses. A growing number of studies on conventional chemical synapses assign Piccolo a role in the recruitment and integration of molecules relevant for both endo- and exocytosis of synaptic vesicles, the dynamic assembly of presynaptic F-actin, as well as the proteostasis of presynaptic proteins, yet a direct function in the structural organization of the active zone has not been uncovered in part due to the expression of multiple alternatively spliced isoforms. We recently identified Piccolino, a Piccolo splice variant specifically expressed in sensory ribbon synapses of the eye and ear. Here we down regulated Piccolino in vivo via an adeno-associated virus-based RNA interference approach and explored the impact on the presynaptic structure of mouse photoreceptor ribbon synapses. Detailed immunocytochemical light and electron microscopical analysis of Piccolino knockdown in photoreceptors revealed a hitherto undescribed photoreceptor ribbon synaptic phenotype with striking morphological changes of synaptic ribbon ultrastructure.
    Frontiers in Cellular Neuroscience 09/2014; 8:259. DOI:10.3389/fncel.2014.00259 · 4.29 Impact Factor
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    • "Splice site prediction analysis using different web tools demonstrated that the site that resulted in the skipping of 101 bp had a very high score as a cryptic splicing donor. The 101 bp-skipped band has not been previously reported as a splicing variant of PCLO in previous studies [19]. Thus, in a minigene assay, activation of the site as a splicing donor resulted in skipping of the last 101 bp of exon 24. "
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    ABSTRACT: The single nucleotide polymorphism (SNP) rs13438494 in intron 24 of PCLO was significantly associated with bipolar disorder in a meta-analysis of genome-wide association studies. In this study, we performed functional minigene analysis and bioinformatics prediction of splicing regulatory sequences to characterize the deep intronic SNP rs13438494. We constructed minigenes with A and C alleles containing exon 24, intron 24, and exon 25 of PCLO to assess the genetic effect of rs13438494 on splicing. We found that the C allele of rs13438494 reduces the splicing efficiency of the PCLO minigene. In addition, prediction analysis of enhancer/silencer motifs using the Human Splice Finder web tool indicated that rs13438494 induces the abrogation or creation of such binding sites. Our results indicate that rs13438494 alters splicing efficiency by creating or disrupting a splicing motif, which functions by binding of splicing regulatory proteins, and may ultimately result in bipolar disorder in affected people.
    PLoS ONE 10/2013; 8(10):e76960. DOI:10.1371/journal.pone.0076960 · 3.23 Impact Factor
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    • "To eliminate the expression of Piccolo in developing neurons, we generated several shRNAs against sequences situated in the N terminus of Piccolo (Exon 1; Fig. 1 A; Fenster and Garner, 2002). This region has been shown to encode segments of the highest molecular weight Piccolo isoforms (∼560 kD; Fig. 1 A; Fenster et al., 2000; Fenster and Garner, 2002) shown previously to localize to presynaptic AZs (Cases-Langhoff et al., 1996; Fenster et al., 2000; Zhai et al., 2000). "
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    ABSTRACT: Active zones are specialized regions of the presynaptic plasma membrane designed for the efficient and repetitive release of neurotransmitter via synaptic vesicle (SV) exocytosis. Piccolo is a high molecular weight component of the active zone that is hypothesized to participate both in active zone formation and the scaffolding of key molecules involved in SV recycling. In this study, we use interference RNAs to eliminate Piccolo expression from cultured hippocampal neurons to assess its involvement in synapse formation and function. Our data show that Piccolo is not required for glutamatergic synapse formation but does influence presynaptic function by negatively regulating SV exocytosis. Mechanistically, this regulation appears to be calmodulin kinase II-dependent and mediated through the modulation of Synapsin1a dynamics. This function is not shared by the highly homologous protein Bassoon, which indicates that Piccolo has a unique role in coupling the mobilization of SVs in the reserve pool to events within the active zone.
    The Journal of Cell Biology 06/2008; 181(5):831-46. DOI:10.1083/jcb.200711167 · 9.83 Impact Factor
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