RESUMO
Small RNA pathways defend the germlines of animals against selfish genetic elements, yet pathway activities need to be contained to prevent silencing of self genes. Here, we reveal a proteolytic mechanism that controls endogenous small interfering (22G) RNA activity in the Caenorhabditis elegans germline to protect genome integrity and maintain fertility. We find that DPF-3, a P-granule-localized N-terminal dipeptidase orthologous to mammalian dipeptidyl peptidase (DPP) 8/9, processes the unusually proline-rich N termini of WAGO-1 and WAGO-3 Argonaute (Ago) proteins. Without DPF-3 activity, these WAGO proteins lose their proper complement of 22G RNAs. Desilencing of repeat-containing and transposon-derived transcripts, DNA damage, and acute sterility ensue. These phenotypes are recapitulated when WAGO-1 and WAGO-3 are rendered resistant to DPF-3-mediated processing, identifying them as critical substrates of DPF-3. We conclude that N-terminal processing of Ago proteins regulates their activity and promotes silencing of selfish genetic elements by ensuring Ago association with appropriate small RNAs.
Assuntos
Proteínas Argonautas/genética , Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/genética , Dipeptidil Peptidases e Tripeptidil Peptidases/genética , Processamento de Proteína Pós-Traducional , RNA de Helmintos/genética , Animais , Proteínas Argonautas/metabolismo , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Dipeptidil Peptidases e Tripeptidil Peptidases/metabolismo , Fertilidade/genética , Proteólise , RNA de Helmintos/antagonistas & inibidores , RNA de Helmintos/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Especificidade por SubstratoRESUMO
TRIM71/LIN-41, a phylogenetically conserved regulator of development, controls stem cell fates. Mammalian TRIM71 exhibits both RNA-binding and protein ubiquitylation activities, but the functional contribution of either activity and relevant primary targets remain poorly understood. Here, we demonstrate that TRIM71 shapes the transcriptome of mouse embryonic stem cells (mESCs) predominantly through its RNA-binding activity. We reveal that TRIM71 binds targets through 3' untranslated region (UTR) hairpin motifs and that it acts predominantly by target degradation. TRIM71 mutations implicated in etiogenesis of human congenital hydrocephalus impair target silencing. We identify a set of primary targets consistently regulated in various human and mouse cell lines, including MBNL1 (Muscleblind-like protein 1). MBNL1 promotes cell differentiation through regulation of alternative splicing, and we demonstrate that TRIM71 promotes embryonic splicing patterns through MBNL1 repression. Hence, repression of MBNL1-dependent alternative splicing may contribute to TRIM71's function in regulating stem cell fates.
Assuntos
Processamento Alternativo/genética , Regulação da Expressão Gênica/genética , Proteínas de Ligação a RNA/genética , Proteínas com Motivo Tripartido/genética , Proteínas com Motivo Tripartido/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Animais , Linhagem Celular Tumoral , Células-Tronco Embrionárias , Humanos , Camundongos , Camundongos Knockout , Mutação , Motivos de Nucleotídeos , Ligação Proteica , Domínios Proteicos/genética , Interferência de RNA , Proteínas de Ligação a RNA/metabolismoRESUMO
N6-methyladenosine (m6A) is the most abundant mRNA modification in eukaryotes, playing crucial roles in multiple biological processes. m6A is catalyzed by the activity of methyltransferase-like 3 (Mettl3), which depends on additional proteins whose precise functions remain poorly understood. Here we identified Zc3h13 (zinc finger CCCH domain-containing protein 13)/Flacc [Fl(2)d-associated complex component] as a novel interactor of m6A methyltransferase complex components in Drosophila and mice. Like other components of this complex, Flacc controls m6A levels and is involved in sex determination in Drosophila We demonstrate that Flacc promotes m6A deposition by bridging Fl(2)d to the mRNA-binding factor Nito. Altogether, our work advances the molecular understanding of conservation and regulation of the m6A machinery.
Assuntos
Proteínas de Transporte/metabolismo , Proteínas de Ligação a DNA/metabolismo , Drosophila melanogaster/fisiologia , Metiltransferases/metabolismo , Proteínas Nucleares/metabolismo , Proteínas de Ligação a RNA/metabolismo , Adenosina/metabolismo , Animais , Proteínas de Ciclo Celular , Linhagem Celular , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/enzimologia , Regulação da Expressão Gênica no Desenvolvimento , Metilação , Camundongos , Células-Tronco Embrionárias Murinas , Transporte Proteico , Precursores de RNA/genética , Splicing de RNA , Fatores de Processamento de RNA , Processos de Determinação Sexual/genéticaRESUMO
Transcription termination determines the ends of transcriptional units and thereby ensures the integrity of the transcriptome and faithful gene regulation. Studies in yeast and human cells have identified the exoribonuclease XRN2 as a key termination factor for protein-coding genes. Here we performed a genome-wide investigation of RNA polymerase II (Pol II) transcription termination in XRN2-deficient Caenorhabditis elegans and observed two distinct modes of termination. Although a subset of genes requires XRN2, termination of other genes appears both independent of, and refractory to, XRN2. XRN2 independence is not merely a consequence of failure to recruit XRN2, since XRN2 is present on-and promotes Pol II accumulation near the polyadenylation sites of-both gene classes. Unexpectedly, promoters instruct the choice of termination mode, but XRN2-independent termination additionally requires a compatible region downstream from the 3' end cleavage site. Hence, different termination mechanisms may work with different configurations of Pol II complexes dictated by promoters.
Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/genética , Exorribonucleases/metabolismo , Regiões Promotoras Genéticas , RNA Polimerase II/metabolismo , Terminação da Transcrição Genética/fisiologia , Animais , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Exorribonucleases/genética , Interferência de RNA , RNA Polimerase II/genética , RNA Mensageiro/genéticaRESUMO
De novo mutations in ADNP, which encodes activity-dependent neuroprotective protein (ADNP), have recently been found to underlie Helsmoortel-Van der Aa syndrome, a complex neurological developmental disorder that also affects several other organ functions 1 . ADNP is a putative transcription factor that is essential for embryonic development 2 . However, its precise roles in transcriptional regulation and development are not understood. Here we show that ADNP interacts with the chromatin remodeller CHD4 and the chromatin architectural protein HP1 to form a stable complex, which we refer to as ChAHP. Besides mediating complex assembly, ADNP recognizes DNA motifs that specify binding of ChAHP to euchromatin. Genetic ablation of ChAHP components in mouse embryonic stem cells results in spontaneous differentiation concomitant with premature activation of lineage-specific genes and in a failure to differentiate towards the neuronal lineage. Molecularly, ChAHP-mediated repression is fundamentally different from canonical HP1-mediated silencing: HP1 proteins, in conjunction with histone H3 lysine 9 trimethylation (H3K9me3), are thought to assemble broad heterochromatin domains that are refractory to transcription. ChAHP-mediated repression, however, acts in a locally restricted manner by establishing inaccessible chromatin around its DNA-binding sites and does not depend on H3K9me3-modified nucleosomes. Together, our results reveal that ADNP, via the recruitment of HP1 and CHD4, regulates the expression of genes that are crucial for maintaining distinct cellular states and assures accurate cell fate decisions upon external cues. Such a general role of ChAHP in governing cell fate plasticity may explain why ADNP mutations affect several organs and body functions and contribute to cancer progression1,3,4. Notably, we found that the integrity of the ChAHP complex is disrupted by nonsense mutations identified in patients with Helsmoortel-Van der Aa syndrome, and this could be rescued by aminoglycosides that suppress translation termination 5 . Therefore, patients might benefit from therapeutic agents that are being developed to promote ribosomal read-through of premature stop codons6,7.
Assuntos
Linhagem da Célula/genética , Proteínas Cromossômicas não Histona/metabolismo , DNA Helicases/metabolismo , Proteínas de Homeodomínio/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Animais , Homólogo 5 da Proteína Cromobox , Eucromatina/genética , Eucromatina/metabolismo , Proteínas de Homeodomínio/genética , Camundongos , Camundongos Endogâmicos C57BL , Células-Tronco Embrionárias Murinas/citologia , Proteínas do Tecido Nervoso/genética , Neurônios/citologia , Nucleossomos/metabolismo , Ligação Proteica , Proteínas Repressoras/metabolismo , Transcrição GênicaRESUMO
Small non-protein coding RNAs are involved in pathways that control the genome at the level of chromatin. In Schizosaccharomyces pombe, small interfering RNAs (siRNAs) are required for the faithful propagation of heterochromatin that is found at peri-centromeric repeats. In contrast to repetitive DNA, protein-coding genes are refractory to siRNA-mediated heterochromatin formation, unless siRNAs are expressed in mutant cells. Here we report the identification of 20 novel mutant alleles that enable de novo formation of heterochromatin at a euchromatic protein-coding gene by using trans-acting siRNAs as triggers. For example, a single amino acid substitution in the pre-mRNA cleavage factor Yth1 enables siRNAs to trigger silent chromatin formation with unparalleled efficiency. Our results are consistent with a kinetic nascent transcript processing model for the inhibition of small-RNA-directed de novo formation of heterochromatin and lay a foundation for further mechanistic dissection of cellular activities that counteract epigenetic gene silencing.
Assuntos
Regulação Fúngica da Expressão Gênica , Inativação Gênica , RNA Mensageiro/genética , RNA Interferente Pequeno/genética , Schizosaccharomyces/genética , Fatores de Poliadenilação e Clivagem de mRNA/genética , Alelos , Substituição de Aminoácidos , Centrômero/química , Centrômero/metabolismo , Montagem e Desmontagem da Cromatina , Perfilação da Expressão Gênica , Heterocromatina/química , Heterocromatina/metabolismo , Cinética , Modelos Genéticos , Anotação de Sequência Molecular , Mutação , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/metabolismo , Schizosaccharomyces/metabolismo , Fatores de Poliadenilação e Clivagem de mRNA/metabolismoRESUMO
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMO
The post-genomic era has seen many advances in our understanding of cancer pathways, yet resistance and tumor heterogeneity necessitate multiple approaches to target even monogenic tumors. Here, we combine phenotypic screening with chemical genetics to identify pre-messenger RNA endonuclease cleavage and polyadenylation specificity factor 3 (CPSF3) as the target of JTE-607, a small molecule with previously unknown target. We show that CPSF3 represents a synthetic lethal node in a subset of acute myeloid leukemia (AML) and Ewing's sarcoma cancer cell lines. Inhibition of CPSF3 by JTE-607 alters expression of known downstream effectors in AML and Ewing's sarcoma lines, upregulates apoptosis and causes tumor-selective stasis in mouse xenografts. Mechanistically, it prevents the release of newly synthesized pre-mRNAs, resulting in read-through transcription and the formation of DNA-RNA hybrid R-loop structures. This study implicates pre-mRNA processing, and specifically CPSF3, as a druggable target providing an avenue to therapeutic intervention in cancer.
Assuntos
Fator de Especificidade de Clivagem e Poliadenilação/metabolismo , Leucemia Mieloide Aguda/metabolismo , Precursores de RNA/metabolismo , Sarcoma de Ewing/metabolismo , Animais , Apoptose/efeitos dos fármacos , Sítios de Ligação , Hidrolases de Éster Carboxílico/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular , Fator de Especificidade de Clivagem e Poliadenilação/genética , Células HEK293 , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Masculino , Espectrometria de Massas , Camundongos , Camundongos Endogâmicos C57BL , Transplante de Neoplasias , Fenótipo , Fenilalanina/análogos & derivados , Fenilalanina/farmacologia , Piperazinas/farmacologia , Ligação Proteica , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/metabolismo , Sarcoma de Ewing/tratamento farmacológicoRESUMO
To gain insight into the mechanistic link between translation termination and nonsense-mediated mRNA decay (NMD), we depleted the ribosome recycling factor ABCE1 in human cells, resulting in an upregulation of NMD-sensitive mRNAs. Suppression of NMD on these mRNAs occurs prior to their SMG6-mediated endonucleolytic cleavage. ABCE1 depletion caused ribosome stalling at termination codons (TCs) and increased ribosome occupancy in 3' UTRs, implying enhanced TC readthrough. ABCE1 knockdown indeed increased the rate of readthrough and continuation of translation in different reading frames, providing a possible explanation for the observed NMD inhibition, since enhanced readthrough displaces NMD activating proteins from the 3' UTR. Our results indicate that stalling at TCs triggers ribosome collisions and activates ribosome quality control. Collectively, we show that improper translation termination can lead to readthrough of the TC, presumably due to ribosome collisions pushing the stalled ribosomes into the 3' UTR, where it can resume translation in-frame as well as out-of-frame.
Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Códon de Terminação/genética , Degradação do RNAm Mediada por Códon sem Sentido/genética , Telomerase/genética , Regiões 3' não Traduzidas/genética , Mudança da Fase de Leitura do Gene Ribossômico/genética , Humanos , Biossíntese de Proteínas/genética , RNA Mensageiro/genética , Ribossomos/genéticaRESUMO
XRN2 is a conserved 5'â3' exoribonuclease that complexes with proteins that contain XRN2-binding domains (XTBDs). In Caenorhabditis elegans (C. elegans), the XTBD-protein PAXT-1 stabilizes XRN2 to retain its activity. XRN2 activity is also promoted by 3'(2'),5'-bisphosphate nucleotidase 1 (BPNT1) through hydrolysis of an endogenous XRN inhibitor 3'-phosphoadenosine-5'-phosphate (PAP). Here, we find through unbiased screening that loss of bpnt-1 function suppresses lethality caused by paxt-1 deletion. This unexpected finding is explained by XRN2 autoregulation, which occurs through repression of a cryptic promoter activity and destabilization of the xrn-2 transcript. De-repression appears to be triggered such that more robust XRN2 perturbation, by elimination of both PAXT-1 and BPNT1, is less detrimental to worm viability than absence of PAXT-1 alone. Indeed, we find that two distinct XRN2 repression mechanisms are alleviated at different thresholds of XRN2 inactivation. Like more than 15% of C. elegans genes, xrn-2 occurs in an operon, and we identify additional operons under its control, consistent with a broader function of XRN2 in polycistronic gene regulation. Regulation occurs through intercistronic regions that link genes in an operon, but a part of the mechanisms may allow XRN2 to operate on monocistronic genes in organisms lacking operons.
Assuntos
Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/genética , Proteínas de Transporte/genética , Exorribonucleases/genética , Nucleotidases/genética , Animais , Caenorhabditis elegans/crescimento & desenvolvimento , Proteínas de Caenorhabditis elegans/antagonistas & inibidores , Proteínas de Caenorhabditis elegans/biossíntese , Proteínas de Transporte/biossíntese , Exorribonucleases/antagonistas & inibidores , Regulação da Expressão Gênica , Genes/genética , Homeostase/genética , Óperon/genética , Mutações Sintéticas Letais/genéticaRESUMO
BACKGROUND: Group B Sox proteins are a highly conserved group of transcription factors that act extensively to coordinate nervous system development in higher metazoans while showing both co-expression and functional redundancy across a broad group of taxa. In Drosophila melanogaster, the two group B Sox proteins Dichaete and SoxNeuro show widespread common binding across the genome. While some instances of functional compensation have been observed in Drosophila, the function of common binding and the extent of its evolutionary conservation is not known. RESULTS: We used DamID-seq to examine the genome-wide binding patterns of Dichaete and SoxNeuro in four species of Drosophila. Through a quantitative comparison of Dichaete binding, we evaluated the rate of binding site turnover across the genome as well as at specific functional sites. We also examined the presence of Sox motifs within binding intervals and the correlation between sequence conservation and binding conservation. To determine whether common binding between Dichaete and SoxNeuro is conserved, we performed a detailed analysis of the binding patterns of both factors in two species. CONCLUSION: We find that, while the regulatory networks driven by Dichaete and SoxNeuro are largely conserved across the drosophilids studied, binding site turnover is widespread and correlated with phylogenetic distance. Nonetheless, binding is preferentially conserved at known cis-regulatory modules and core, independently verified binding sites. We observed the strongest binding conservation at sites that are commonly bound by Dichaete and SoxNeuro, suggesting that these sites are functionally important. Our analysis provides insights into the evolution of group B Sox function, highlighting the specific conservation of shared binding sites and suggesting alternative sources of neofunctionalisation between paralogous family members.
Assuntos
Proteínas de Drosophila/metabolismo , Drosophila/metabolismo , Fatores de Transcrição SOX/metabolismo , Animais , Sequência de Bases , Sítios de Ligação , Hibridização Genômica Comparativa , Drosophila/genética , Proteínas de Drosophila/genética , Evolução Molecular , Redes Reguladoras de Genes , Genoma , Análise de Componente Principal , Ligação Proteica , Elementos Reguladores de Transcrição , Fatores de Transcrição SOX/genética , Análise de Sequência de DNARESUMO
Acute respiratory distress syndrome (ARDS) is the main complication of coronavirus disease 2019 (COVID-19), requiring admission to the intensive care unit (ICU). Despite extensive immune profiling of COVID-19 patients, to what extent COVID-19-associated ARDS differs from other causes of ARDS remains unknown. To address this question, here, we build 3 cohorts of patients categorized in COVID-19-ARDS+, COVID-19+ARDS+, and COVID-19+ARDS-, and compare, by high-dimensional mass cytometry, their immune landscape. A cell signature associating S100A9/calprotectin-producing CD169+ monocytes, plasmablasts, and Th1 cells is found in COVID-19+ARDS+, unlike COVID-19-ARDS+ patients. Moreover, this signature is essentially shared with COVID-19+ARDS- patients, suggesting that severe COVID-19 patients, whether or not they experience ARDS, display similar immune profiles. We show an increase in CD14+HLA-DRlow and CD14lowCD16+ monocytes correlating to the occurrence of adverse events during the ICU stay. We demonstrate that COVID-19-associated ARDS displays a specific immune profile and may benefit from personalized therapy in addition to standard ARDS management.
Assuntos
COVID-19/patologia , Leucócitos Mononucleares/metabolismo , Síndrome do Desconforto Respiratório/imunologia , Idoso , COVID-19/complicações , COVID-19/virologia , Estudos de Coortes , Evolução Molecular , Feminino , Antígenos HLA-DR/metabolismo , Humanos , Unidades de Terapia Intensiva , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/imunologia , Receptores de Lipopolissacarídeos/metabolismo , Aprendizado de Máquina , Masculino , Pessoa de Meia-Idade , Monócitos/citologia , Monócitos/imunologia , Monócitos/metabolismo , Síndrome do Desconforto Respiratório/etiologia , Síndrome do Desconforto Respiratório/patologia , SARS-CoV-2/isolamento & purificação , Lectina 1 Semelhante a Ig de Ligação ao Ácido Siálico/metabolismo , Células Th1/citologia , Células Th1/imunologia , Células Th1/metabolismoRESUMO
Adenine auxotrophy is a commonly used non-selective genetic marker in yeast research. It allows investigators to easily visualize and quantify various genetic and epigenetic events by simply reading out colony color. However, manual counting of large numbers of colonies is extremely time-consuming, difficult to reproduce and possibly inaccurate. Using cutting-edge neural networks, we have developed a fully automated pipeline for colony segmentation and classification, which speeds up white/red colony quantification 100-fold over manual counting by an experienced researcher. Our approach uses readily available training data and can be smoothly integrated into existing protocols, vastly speeding up screening assays and increasing the statistical power of experiments that employ adenine auxotrophy.
Assuntos
Contagem de Colônia Microbiana/métodos , Aprendizado Profundo , Ensaios de Triagem em Larga Escala , Contagem de Colônia Microbiana/normas , Processamento de Imagem Assistida por Computador , Redes Neurais de Computação , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , LevedurasRESUMO
The assembly of large multimeric complexes in the crowded cytoplasm is challenging. Here we reveal a mechanism that ensures accurate production of the yeast proteasome, involving ribosome pausing and co-translational assembly of Rpt1 and Rpt2. Interaction of nascent Rpt1 and Rpt2 then lifts ribosome pausing. We show that the N-terminal disordered domain of Rpt1 is required to ensure efficient ribosome pausing and association of nascent Rpt1 protein complexes into heavy particles, wherein the nascent protein complexes escape ribosome quality control. Immunofluorescence and in situ hybridization studies indicate that Rpt1- and Rpt2-encoding messenger RNAs co-localize in these particles that contain, and are dependent on, Not1, the scaffold of the Ccr4-Not complex. We refer to these particles as Not1-containing assemblysomes, as they are smaller than and distinct from other RNA granules such as stress granules and GW- or P-bodies. Synthesis of Rpt1 with ribosome pausing and Not1-containing assemblysome induction is conserved from yeast to human cells.
Assuntos
Complexo de Endopeptidases do Proteassoma/metabolismo , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Algoritmos , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Genoma Fúngico/genética , Humanos , Hibridização In Situ , Masculino , Oligonucleotídeos/genética , Oligonucleotídeos/metabolismo , Complexo de Endopeptidases do Proteassoma/genética , Ligação Proteica , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
Eukaryotic gene expression is heavily regulated at the transcriptional and post-transcriptional levels. An additional layer of regulation occurs co-transcriptionally through processing and decay of nascent transcripts physically associated with chromatin. This process involves RNA interference (RNAi) machinery and is well documented in yeast, but little is known about its conservation in mammals. Here we show that Dgcr8 and Drosha physically associate with chromatin in murine embryonic stem cells (mES), specifically with a subset of transcribed coding and noncoding genes. Dgcr8 recruitment to chromatin is dependent on transcription as well as methyltransferase-like 3 (Mettl3), which catalyzes RNA N6-methyladenosine (m6A). Intriguingly, we found that acute temperature stress causes radical relocalization of Dgcr8 and Mettl3 to heat-shock genes, where they act to co-transcriptionally mark mRNAs for subsequent RNA degradation. Together, our findings elucidate a novel mode of co-transcriptional gene regulation, in which m6A serves as a chemical mark that instigates subsequent post-transcriptional RNA-processing events.
Assuntos
Adenosina/metabolismo , Regulação da Expressão Gênica , Estabilidade de RNA , RNA/metabolismo , Transcrição Gênica , Animais , Cromatina/metabolismo , Metilação , Metiltransferases/metabolismo , Camundongos , Células-Tronco Embrionárias Murinas/metabolismo , Ligação Proteica , Proteínas de Ligação a RNA/metabolismo , Ribonuclease III/metabolismoRESUMO
Drosophila melanogaster has been widely used as a model of human Mendelian disease, but its value in modeling complex disease has received little attention. Fly models of complex disease would enable high-resolution mapping of disease-modifying loci and the identification of novel targets for therapeutic intervention. Here, we describe a fly model of permanent neonatal diabetes mellitus and explore the complexity of this model. The approach involves the transgenic expression of a misfolded mutant of human preproinsulin, hINS(C96Y), which is a cause of permanent neonatal diabetes. When expressed in fly imaginal discs, hINS(C96Y) causes a reduction of adult structures, including the eye, wing, and notum. Eye imaginal discs exhibit defects in both the structure and the arrangement of ommatidia. In the wing, expression of hINS(C96Y) leads to ectopic expression of veins and mechano-sensory organs, indicating disruption of wild-type signaling processes regulating cell fates. These readily measurable "disease" phenotypes are sensitive to temperature, gene dose, and sex. Mutant (but not wild-type) proinsulin expression in the eye imaginal disc induces IRE1-mediated XBP1 alternative splicing, a signal for endoplasmic reticulum stress response activation, and produces global change in gene expression. Mutant hINS transgene tester strains, when crossed to stocks from the Drosophila Genetic Reference Panel, produce F1 adults with a continuous range of disease phenotypes and large broad-sense heritability. Surprisingly, the severity of mutant hINS-induced disease in the eye is not correlated with that in the notum in these crosses, nor with eye reduction phenotypes caused by the expression of two dominant eye mutants acting in two different eye development pathways, Drop (Dr) or Lobe (L), when crossed into the same genetic backgrounds. The tissue specificity of genetic variability for mutant hINS-induced disease has, therefore, its own distinct signature. The genetic dominance of disease-specific phenotypic variability in our model of misfolded human proinsulin makes this approach amenable to genome-wide association study in a simple F1 screen of natural variation.