ELAV, a Drosophila neuron-specific protein, mediates the generation of an alternatively spliced neural protein isoform (original) (raw)
Related papers
Molecular and Cellular Biology, 2000
Although the Drosophila melanogaster erect wing (ewg) gene is broadly transcribed in adults, an unusual posttranscriptional regulation involving alternative and inefficient splicing generates a 116-kDa EWG protein in neurons, while protein expression elsewhere or of other isoforms is below detection at this stage. This posttranscriptional control is important, as broad expression of EWG can be lethal. In this paper, we show that ELAV, a neuron-specific RNA binding protein, is necessary to regulate EWG protein expression in ELAV-null eye imaginal disc clones and that ELAV is sufficient for EWG expression in wing disc imaginal tissue after ectopic expression. Further, analysis of EWG expression elicited from intron-containing genomic transgenes and cDNA minitransgenes in ELAV-deficient eye discs shows that this regulation is dependent on the presence of ewg introns. Analyses of the ewg splicing patterns in wild-type and ELAV-deficient eye imaginal discs and in wild-type and ectopic ELAV-expressing wing imaginal discs, show that certain neuronal splice isoforms correspond to ELAV levels. The data presented in this paper are consistent with a mechanism in which ELAV increases the splicing efficiency of ewg transcripts in alternatively spliced regions rather than with a mechanism in which stability of specific splice forms is enhanced by ELAV. Additionally, we report that ELAV promotes a neuron-enriched splice isoform of Drosophila armadillo transcript. ELAV, however, is not involved in all neuron-enriched splice events.
Genes & Development, 2001
Drosophila melanogaster neural-specific protein, ELAV, has been shown to regulate the neural-specific splicing of three genes:neuroglian (nrg), erect wing, andarmadillo. Alternative splicing of the nrg transcript involves alternative inclusion of a 3′-terminal exon. Here, using a minigene reporter, we show that the nrg alternatively spliced intron (nASI) has all the determinants required to recreate proper neural-specific RNA processing seen with the endogenousnrg transcript, including regulation by ELAV. An in vitro UV cross-linking assay revealed that ELAV from nuclear extracts cross-links to four distinct sites along the 3200 nucleotide longnASI; one EXS is positioned at the polypyrimidine tract of the default 3′ splice site. ELAV cross-linking sites (EXSs) have in common long tracts of (U)-rich sequence rather than a precise consensus; moreover, each tract has at least two 8/10U elements; their importance is validated by mutant transgene reporter analysis. Further, we propose cr...
ELAV/Hu RNA binding proteins determine multiple programs of neural alternative splicing
PLOS Genetics
ELAV/Hu factors are conserved RNA binding proteins (RBPs) that play diverse roles in mRNA processing and regulation. The founding member,DrosophilaElav, was recognized as a vital neural factor 35 years ago. Nevertheless, little was known about its impacts on the transcriptome, and potential functional overlap with its paralogs. Building on our recent findings that neural-specific lengthened 3’ UTR isoforms are co-determined by ELAV/Hu factors, we address their impacts on splicing. While only a few splicing targets ofDrosophilaare known, ectopic expression of each of the three family members (Elav, Fne and Rbp9) alters hundreds of cassette exon and alternative last exon (ALE) splicing choices. Reciprocally, double mutants ofelav/fne, but notelavalone, exhibit opposite effects on both classes of regulated mRNA processing events in larval CNS. While manipulation ofDrosophilaELAV/Hu RBPs induces both exon skipping and inclusion, characteristic ELAV/Hu motifs are enriched only within int...
Differential splicing generates a nervous system—Specific form of drosophila neuroglian
Neuron, 1990
We recently described the characterization and cloning of Drosophila neuroglian, a member of the immunoglobulin superfamily. Neuroglian contains six immunoglobulin-like domains and five fibronectin type III domains and shows strong sequence homology to the mouse neural cell adhesion molecule 11. Here we show that the neuroglian gene generates at least two different protein products by tissue-specific alternative splicing. The two protein forms differ in their cytoplasmic domains. The long form is restricted to the surface of neurons in the CNS and neurons and some support cells in the PNS; in contrast, the short form is expressed on a wide range of other cells and tissues. Thus, whereas the mouse 11 gene appears to encode only one protein that functions largely as a neural cell adhesion molecule, its Drosophila homolog, the neuroglian gene, encodes at least two protein forms that may play two different roles, one as a neural cell adhesion molecule and the other as a more general cell adhesion molecule involved in other tissues and imaginal disc morphogenesis.
Developmental Dynamics, 2007
Drosophila embryonic nervous system can be monitored with the marker Reversedpolarity (Repo), whereas neurons lack Repo and express the RNA-binding protein ELAV (Embryonic Lethal, Abnormal Vision). Since the first description of the ELAV protein distribution in 1991 (Robinow and White), it is believed that ELAV is an exclusive neuronal and postmitotic marker. Looking at ELAV expression, we unexpectedly observed that, in addition to neurons, ELAV is transiently expressed in embryonic glial cells. Furthermore, it is transiently present in the proliferating longitudinal glioblast, and it is transcribed in embryonic neuroblasts. Likewise, elav-Gal4 lines, which are generally used as postmitotic neuronal driver lines, show expression in neural progenitor cells and nearly all embryonic glial cells. Thus, in the embryo, elav can no longer be considered an exclusive marker or driver for postmitotic neurons. elav loss-offunction mutants show no obvious effects on the number and pattern of embryonic glia. Developmental Dynamics 236:3562-3568, 2007.
1993
Regulated gene activity is crucial to the formation and function of the nervous system. It is well known that gene regulation can occur at the transcriptional, post-transcriptional, translational, and post-translational levels. In this review our focus has been on the post-transcriptional regulation in neurons and on neural-specific RNA binding proteins that may be involved in post-transcriptional modulation of gene activity. We have taken advantage of this opportunity to review our work on the efav gene of Drosophilu melanoguster which encodes a neural-specific RNA binding protein and relate it to other members of this elav-like gene family. We report new data that suggests that elm is post-transcriptionally regulated and we demonstrate that below-threshold levels of ELAV protein severely affects neuronal differentiation.
Molecular cell, 2014
Alternative splicing is important for the development and function of the nervous system, but little is known about the differences in alternative splicing between distinct types of neurons. Furthermore, the factors that control cell-type-specific splicing and the physiological roles of these alternative isoforms are unclear. By monitoring alternative splicing at single-cell resolution in Caenorhabditis elegans, we demonstrate that splicing patterns in different neurons are often distinct and highly regulated. We identify two conserved RNA-binding proteins, UNC-75/CELF and EXC-7/Hu/ELAV, which regulate overlapping networks of splicing events in GABAergic and cholinergic neurons. We use the UNC-75 exon network to discover regulators of synaptic transmission and to identify unique roles for isoforms of UNC-64/Syntaxin, a protein required for synaptic vesicle fusion. Our results indicate that combinatorial regulation of alternative splicing in distinct neurons provides a mechanism to s...
Molecular and Cellular Biology, 2007
Deciphering the role of alternative splicing in developmental processes relies on the identification of key genes whose expression is controlled by splicing regulators throughout the growth of a whole organism. Modulating the expression levels of five SR proteins in the developing eye of Drosophila melanogaster revealed that these splicing factors induce various phenotypic alterations in eye organogenesis and also affect viability. Although the SR proteins dASF/SF2 and B52 caused defects in ommatidia structure, only B52 impaired normal axonal projections of photoreceptors and neurogenesis in visual ganglia. Microarray analyses revealed that many transcripts involved in brain organogenesis have altered splicing profiles upon both loss and gain of B52 function. Conversely, a large proportion of transcripts regulated by dASF/SF2 are involved in eye development. These differential and specific effects of SR proteins indicate that they function to confer accuracy to developmental gene expression programs by facilitating the cell lineage decisions that underline the generation of tissue identities.
bioRxiv (Cold Spring Harbor Laboratory), 2024
The regulation of cell-specific gene expression patterns during development requires the coordinated actions of hundreds of proteins, including transcription factors, processing enzymes, and many RNA binding proteins (RBPs). RBPs often become associated with a nascent transcript immediately after its production and are uniquely positioned to coordinate concurrent processing and quality control steps. Since RNA binding proteins can regulate multiple post-transcriptional processing steps for many mRNA transcripts, mutations within RBP-encoding genes often lead to pleiotropic effects that alter the physiology of multiple cell types. Thus, identifying the mRNA processing steps where an RBP functions and the effects of RBP loss on gene expression patterns can provide a better understanding of both tissue physiology and mechanisms of disease. In the current study, we have investigated the coordination of mRNA splicing and polyadenylation facilitated by the Drosophila RNA binding protein Nab2, an evolutionary conserved ortholog of human ZC3H14. ZC3H14 loss in human patients has previously been linked to alterations in nervous system function and disease. Both fly Nab2 and vertebrate ZC3H14 bind to polyadenosine RNA and have been implicated in the control of poly(A) tail length. Interestingly, we show that fly Nab2 functionally interacts with components of the spliceosome, suggesting that this family of RNA biding proteins may also regulate alternative splicing of mRNA transcripts. Using RNA-sequencing approaches, we show that Nab2 loss causes widespread changes in alternative splicing and intron retention. These changes in splicing cause alterations in the abundance of protein isoforms encoded by the affected transcripts and may contribute to phenotypes, such as decreases in viability and alterations in brain morphology, observed in Nab2 null flies. Overall, these studies highlight the importance of RNA binding proteins in the coordination of post-transcriptional gene expression regulation and potentially identify a class of proteins that can coordinate multiple processing events for specific mRNA transcripts. .
Nova-1 Regulates Neuron-Specific Alternative Splicing and Is Essential for Neuronal Viability
Neuron, 2000
ing the glycine, GABA (Macdonald, 1995), dopamine (Picetti et al., 1997), serotonin (Claeysen et al., 1998), opioid We have combined genetic and biochemical ap-(Zaki et al., 1996), and metabotropic glutamate (Conn proaches to analyze the function of the RNA-binding