Fly cell RNAi screen identifies "first in vivo mediator of hypercapnic immune suppression" in study relevant to COPD and other lung disorders

Congrats to Taneli and the rest of the team on this report of a screen performed at the DRSC!

Helenius IT, Haake RJ, Kwon YJ, Hu JA, Krupinski T, Casalino-Matsuda SM, Sporn PH, Sznajder JI, Beitel GJ. Identification of Drosophila Zfh2 as a Mediator of Hypercapnic Immune Regulation by a Genome-Wide RNA Interference Screen. J Immunol. 2015 Dec 7. pii: 1501708. PMID: 26643480.

From the abstract: "Hypercapnia, elevated partial pressure of CO₂ in blood and tissue, develops in many patients with chronic severe obstructive pulmonary disease and other advanced lung disorders. Patients with advanced disease frequently develop bacterial lung infections ... We previously demonstrated that hypercapnia suppresses induction of NF-κB-regulated innate immune response genes ... However, the molecular mediators of hypercapnic immune suppression are undefined. In this study, we report a genome-wide RNA interference screen in Drosophila S2* cells stimulated with bacterial peptidoglycan. The screen identified 16 genes with human orthologs whose knockdown reduced hypercapnic suppression of the gene encoding the antimicrobial peptide Diptericin (Dipt), but did not increase Dipt mRNA levels in air. In vivo tests of one of the strongest screen hits, zinc finger homeodomain 2 (Zfh2; mammalian orthologs ZFHX3/ATBF1 and ZFHX4), demonstrate that reducing zfh2 function using a mutation or RNA interference improves survival of flies exposed to elevated CO₂ and infected with Staphylococcus aureus. Tissue-specific knockdown of zfh2 in the fat body, the major immune and metabolic organ of the fly, mitigates hypercapnia-induced reductions ... and improves resistance of CO₂-exposed flies to infection. Zfh2 mutations also partially rescue hypercapnia-induced delays in egg hatching ... Taken together, to our knowledge, these results identify Zfh2 as the first in vivo mediator of hypercapnic immune suppression."

Report of CRISPR-Cas modification of the emerging pest Drosophila suzukii

Interesting. Chance meeting of #blueberry farmer in #Maine brought #Drosophila suzukii #pest issue to life for me. https://t.co/MCDHHKIHV7

— Stephanie Mohr (@smohrfly) January 2, 2016

RNAi as insecticide

David O'Brachta at the IGT-RCN reports on insecticidal dsRNA encoded by corn, which is "moving to the field" currently "for seed production and breeding only."  Read the story here.

Endogenous roles of Dicer-2--new report suggests link to Toll

Wang Z, Wu D, Liu Y, Xia X, Gong W, Qiu Y, Yang J, Zheng Y, Li J, Wang YF, Xiang Y, Hu Y, Zhou X. Drosophila Dicer-2 has an RNA interference-independent function that modulates Toll immune signaling. Sci Adv. 2015 Oct 16;1(9):e1500228. PMID: 26601278; PMCID: PMC4646792.

From the abstract: "Dicer-2 is the central player for small interfering RNA biogenesis in the Drosophila RNA interference (RNAi) pathway. Intriguingly, we found that Dicer-2 has an unconventional RNAi-independent function that positively modulates Toll immune signaling ... The loss of Dicer-2 expression makes fruit flies more susceptible to fungal infection. We further revealed that Dicer-2 posttranscriptionally modulates Toll signaling because Dicer-2 is required for the proper expression of Toll protein ... Dicer-2 directly binds to the 3' untranslated region (3'UTR) of Toll mRNA via its PAZ (Piwi/Argonaute/Zwille) domain and is required for protein translation mediated by Toll 3'UTR. ... our findings ... indicate an unexpected intersection of the RNAi pathway and the Toll pathway, and provide new insights into Toll immune signaling, Drosophila Dicer-2, and probably Dicer and Dicer-related proteins in other organisms."

Drosophila cell team at the DGRC reports integrase-mediated cassette exchange approach to production of clonal transgenic fly cell lines

Lucy Cherbas1, Jennifer Hackney, Lei Gong, Claire Salzer, Eric Mauser, Dayu Zhang and Peter Cherbas. Tools for Targeted Genome Engineering of Established Drosophila Cell Lines.
Early online in G3.

From the abstract: "We describe an adaptation of ΦC31 integrase-mediated targeted cassette exchange for use in Drosophila cell lines. Single copies of an attP-bounded docking platform carrying a GFP-expression marker, with or without insulator elements flanking the attP sites, were inserted by P-element transformation into the Kc167 and Sg4 cell lines; each of the resulting docking site lines carries a single mapped copy of one of the docking platforms. ... We describe procedures for isolating cells carrying the substitutions ... When compared with clonal lines made by traditional transformation methods ... targeted insertion lines give more uniform expression, lower basal expression and higher induction ratios. Targeted substitution, though intricate, affords results that should greatly improve comparative expression assays – a major emphasis of cell-based studies." 

RNAi-based screen for interaction with chd1

Sharon Kim, Lakshmi Bugga, Eugenie S. Hong, Rebecca Zabinsky, Rebecca G. Edwards, Parimal A. Deodhar and Jennifer A. Armstrong. An RNAi-Based Candidate Screen for Modifiers of the CHD1 Chromatin Remodeler and Assembly Factor in Drosophila melanogaster.
Early online at G3.

From the abstract: "... CHD1 ... is present at active genes where it participates in histone turnover and recycling during transcription. ... We found that over-expression of the CHD1 results in defects in wing development and utilized this fully penetrant and reliable phenotype to conduct a small-scale RNAi-based candidate screen to identify genes that functionally interact with chd1 in vivo. ..."

in vivo RNAi used to validate at gene level hits in genome-wide deficiency screen for enhancers and suppressors of Na (+) /K (+) ATPase alleles

Talsma AD, Chaves JF, LaMonaca A, Wieczorek ED, Palladino MJ. Genome-wide screen for modifiers of Na (+) /K (+) ATPase alleles identifies critical genetic loci. Mol Brain. 2014 Dec 5;7:89. doi: 10.1186/s13041-014-0089-3. PMID: 25476251; PMCID: PMC4302446.

From the abstract: "Mutations affecting the Na (+) / K (+) ATPase (a.k.a. the sodium-potassium pump) genes cause conditional locomotor phenotypes in flies and three distinct complex neurological diseases in humans. More than 50 mutations have been identified affecting the human ATP1A2 and ATP1A3 genes that are known to cause rapid-onset Dystonia Parkinsonism, familial hemiplegic migraine, alternating hemiplegia of childhood, and variants of familial hemiplegic migraine with neurological complications including seizures and various mood disorders. In flies, mutations affecting the ATPalpha gene have dramatic phenotypes including altered longevity, neural dysfunction, neurodegeneration, myodegeneration, and striking locomotor impairment. ... We performed a genome-wide deficiency screen ... to identify novel modifier loci. A secondary screen confirmed allele-specificity of the interactions and many of the interactions were mapped to single genes and subsequently validated. We successfully identified 64 modifier loci and used classical mutations and RNAi to confirm 50 single gene interactions. ... These data demonstrate there are many loci capable of modifying ATPalpha dysfunction, which may provide the basis for modifying migraine, locomotor and seizure dysfunction in animals."