Gene Symbol: Psi
Description: P-element somatic inhibitor
Alias: CG8912, Dmel\CG8912, EG:EG0003.2, PSI, P-element somatic inhibitor, CG8912-PA, CG8912-PB, CG8912-PC, P element somatic inhibitor, P-element somatic inhibitor protein, Psi-PA, Psi-PB, Psi-PC
Species: fruit fly

Top Publications

  1. Amarasinghe A, MacDiarmid R, Adams M, Rio D. An in vitro-selected RNA-binding site for the KH domain protein PSI acts as a splicing inhibitor element. RNA. 2001;7:1239-53 pubmed
    b>P element somatic inhibitor (PSI) is a 97-kDa RNA-binding protein with four KH motifs that is involved in the inhibition of splicing of the Drosophila P element third intron (IVS3) in somatic cells...
  2. Labourier E, Adams M, Rio D. Modulation of P-element pre-mRNA splicing by a direct interaction between PSI and U1 snRNP 70K protein. Mol Cell. 2001;8:363-73 pubmed
    P-element somatic inhibitor (PSI) is a KH domain-containing splicing factor highly expressed in Drosophila somatic tissues...
  3. Blanchette M, Green R, Brenner S, Rio D. Global analysis of positive and negative pre-mRNA splicing regulators in Drosophila. Genes Dev. 2005;19:1306-14 pubmed
    ..identified the alternative splice events controlled by four splicing regulators: dASF/SF2, B52/SRp55, hrp48, and PSI. The number of events controlled by each of these factors was found to be highly variable: dASF/SF2 strongly ..
  4. Ignjatovic T, Yang J, Butler J, Neuhaus D, Nagai K. Structural basis of the interaction between P-element somatic inhibitor and U1-70k essential for the alternative splicing of P-element transposase. J Mol Biol. 2005;351:52-65 pubmed
    ..In somatic cells, the P-element somatic inhibitor (PSI) protein binds to exon 3 of the pre-mRNA and recruits U1 small nuclear ribonucleoprotein (snRNP) to the F1 pseudo-..
  5. Siebel C, Fresco L, Rio D. The mechanism of somatic inhibition of Drosophila P-element pre-mRNA splicing: multiprotein complexes at an exon pseudo-5' splice site control U1 snRNP binding. Genes Dev. 1992;6:1386-401 pubmed
  6. Siebel C, Admon A, Rio D. Soma-specific expression and cloning of PSI, a negative regulator of P element pre-mRNA splicing. Genes Dev. 1995;9:269-83 pubmed
    b>PSI is an RNA-binding protein involved in repressing splicing of the P element third intron in Drosophila somatic cell extracts...
  7. Siebel C, Kanaar R, Rio D. Regulation of tissue-specific P-element pre-mRNA splicing requires the RNA-binding protein PSI. Genes Dev. 1994;8:1713-25 pubmed somatic extracts, providing direct evidence that inhibition requires this protein, P-element somatic inhibitor (PSI)...
  8. Adams M, Tarng R, Rio D. The alternative splicing factor PSI regulates P-element third intron splicing in vivo. Genes Dev. 1997;11:129-38 pubmed
    ..The P-element somatic inhibitor protein (PSI) is a component of this ribonucleoprotein complex and is required for inhibition of IVS3 splicing in vitro...
  9. Wang Q, Taliaferro J, Klibaite U, Hilgers V, Shaevitz J, Rio D. The PSI-U1 snRNP interaction regulates male mating behavior in Drosophila. Proc Natl Acad Sci U S A. 2016;113:5269-74 pubmed publisher
    ..Using genome-wide approaches and quantitative behavioral assays, we show that the P-element somatic inhibitor (PSI) and its interaction with the U1 small nuclear ribonucleoprotein complex (snRNP) control male courtship behavior...

More Information


  1. Oas S, Bryantsev A, Cripps R. Arrest is a regulator of fiber-specific alternative splicing in the indirect flight muscles of Drosophila. J Cell Biol. 2014;206:895-908 pubmed publisher
    ..Our observations provide insight into a transcriptional and splicing regulatory network for muscle fiber specification. ..
  2. Chmiel N, Rio D, Doudna J. Distinct contributions of KH domains to substrate binding affinity of Drosophila P-element somatic inhibitor protein. RNA. 2006;12:283-91 pubmed
    Drosophila P-element somatic inhibitor protein (PSI) regulates splicing of the P-element transposase pre-mRNA by binding a pseudo-splice site upstream of the authentic splice site using four tandem KH-type RNA binding motifs...
  3. Guo L, Zaysteva O, Nie Z, Mitchell N, Amanda Lee J, Ware T, et al. Defining the essential function of FBP/KSRP proteins: Drosophila Psi interacts with the mediator complex to modulate MYC transcription and tissue growth. Nucleic Acids Res. 2016;44:7646-58 pubmed publisher
    ..Using Drosophila, where the three mammalian FBP proteins (FBP1-3) are represented by one ortholog, Psi, we demonstrate the primary developmental role is control of cell and tissue growth...
  4. Li X, Chatterjee N, Spirohn K, Boutros M, Bohmann D. Cdk12 Is A Gene-Selective RNA Polymerase II Kinase That Regulates a Subset of the Transcriptome, Including Nrf2 Target Genes. Sci Rep. 2016;6:21455 pubmed publisher
    ..We suggest that Cdk12 acts as a gene-selective Pol II kinase that engages a global shift in gene expression to switch cells from a metabolically active state to "stress-defence mode" when challenged by external stress. ..
  5. Taliaferro J, Marwha D, Aspden J, Mavrici D, Cheng N, Kohlstaedt L, et al. The Drosophila splicing factor PSI is phosphorylated by casein kinase II and tousled-like kinase. PLoS ONE. 2013;8:e56401 pubmed publisher
    ..Here, we show that the Drosophila splicing factor P element Somatic Inhibitor (PSI) is phosphorylated at at least two different sites by at minimum two different kinases, casein ..
  6. Cranna N, Mitchell N, Hannan R, Quinn L. Hfp, the Drosophila homolog of the mammalian c-myc transcriptional-repressor and tumor suppressor FIR, inhibits dmyc transcription and cell growth. Fly (Austin). 2011;5:129-33 pubmed
  7. Smith C, Valcarcel J. Alternative pre-mRNA splicing: the logic of combinatorial control. Trends Biochem Sci. 2000;25:381-8 pubmed
    ..Its modulation is achieved through the combinatorial interplay of positive and negative regulatory signals present in the RNA, which are recognized by complexes composed of members of the hnRNP and SR protein families. ..
  8. Grams R, Korge G. The mub gene encodes a protein containing three KH domains and is expressed in the mushroom bodies of Drosophila melanogaster. Gene. 1998;215:191-201 pubmed
    ..Null mutants of the mub gene do not exhibit a visible mutant phenotype. We speculate, therefore, that the mub gene is involved in learning and memory processes. ..
  9. Lee Y, Langley C. Long-term and short-term evolutionary impacts of transposable elements on Drosophila. Genetics. 2012;192:1411-32 pubmed publisher
  10. Telonis Scott M, Kopp A, Wayne M, Nuzhdin S, McIntyre L. Sex-specific splicing in Drosophila: widespread occurrence, tissue specificity and evolutionary conservation. Genetics. 2009;181:421-34 pubmed publisher
    ..females. We found that all six loci are themselves spliced sex specifically in gonads and heads, suggesting that regulatory hierarchies based on alternative splicing may be an important feature of sexual differentiation. ..
  11. Li Y, Rao X, MATTOX W, Amos C, Liu B. RNA-Seq Analysis of Differential Splice Junction Usage and Intron Retentions by DEXSeq. PLoS ONE. 2015;10:e0136653 pubmed publisher
  12. Chabot B. Directing alternative splicing: cast and scenarios. Trends Genet. 1996;12:472-8 pubmed
    ..The identity of splicing signals, the presence of modulating elements and differences in the distribution of RNA-binding proteins are key determinants involved in the tissue-specific regulation of splice site selection. ..
  13. Siebel C, Rio D. Regulated splicing of the Drosophila P transposable element third intron in vitro: somatic repression. Science. 1990;248:1200-8 pubmed