Screening and Analysis of Janelia FlyLight Project Enhancer-Gal4 Strains Identifies Multiple Gene Enhancers Active During Hematopoiesis in Normal and Wasp-ChallengedDrosophilaLarvae

Abstract

A GFP expression screen has been conducted on >1000 Janelia FlyLight Project enhancer-Gal4 lines to identify transcriptional enhancers active in the larval hematopoietic system. A total of 190 enhancers associated with 87 distinct genes showed activity in cells of the third instar larval lymph gland and hemolymph. That is, gene enhancers were active in cells of the lymph gland posterior signaling center (PSC), medullary zone (MZ), and/or cortical zone (CZ), while certain of the transcriptional control regions were active in circulating hemocytes. Phenotypic analyses were undertaken on 81 of these hematopoietic-expressed genes, with nine genes characterized in detail as to gain- and loss-of-function phenotypes in larval hematopoietic tissues and blood cells. These studies demonstrated the functional requirement of the cut gene for proper PSC niche formation, the hairy, Btk29A, and E2F1 genes for blood cell progenitor production in the MZ domain, and the longitudinals lacking, dFOXO, kayak, cap-n-collar, and delilah genes for lamellocyte induction and/or differentiation in response to parasitic wasp challenge and infestation of larvae. Together, these findings contribute substantial information to our knowledge of genes expressed during the larval stage of Drosophila hematopoiesis and newly identify multiple genes required for this developmental process.

CCAP regulates feeding behavior via the NPF pathway in Drosophila adults

“…Currently, it is not understood which neuropeptides regulate NPF neurons under starvation conditions. To look for genes that may regulate NPF signaling, the FlyLight database (29) was searched for available GAL4 lines having an expression pattern similar to NPF-expressing neurons. The GAL4 line R64F05 appeared to express in a pattern reminiscent of 2 dorsal median NPF-expressing neurons, designated P1 neurons (30).…”

“…CCAP Signaling Regulates NPF Neural Activity. Given that R64F05-GAL4 was only detected in P1 NPF neurons, we wanted to understand if dorsal median (P1) and dorsal lateral (L1-I) NPF neurons reacted differentially under starvation conditions (29). To do this, brains from wild-type male flies, which had undergone either acute (3, 6, and 9 h) or chronic (24 h) starvation, were stained for NPF expression.…”

A single-cell survey ofDrosophilablood

“…The w;UAS-nlsGFP::lacZ;btlGAL4 line is a Perrimon Lab stock. BcF6-mCherry and msn-mCherry fly stocks were obtained from Dr. Robert Schulz (Tokusumi et al, 2017). Antibodies: Antibodies against Atilla [anti-mouse L1abc (1:100 dilution)] and PPO1 (1:1000 dilution) were a generous gift from István Ando (Kurucz et al, 2007).…”

Oxidised metabolites of the omega-6 fatty acid linoleic acid activate dFOXO

“…Lamellocytes are normally rare but, in response to inflammatory stimuli, differentiate from plasmatocytes and aggregate to produce nodules called "melanotic tumours" (Stofanko et al, 2010). Lamellocyte differentiation is regulated by inflammatory signaling pathways, including the JAK/STAT and Jun N-terminal kinase (JNK) pathways (Zettervall et al, 2004;Tokusumi et al, 2009aTokusumi et al, , 2009b, with Drosophila c-Jun and FOXO TFs activated during lamellocyte differentiation (Tokusumi et al, 2017). Lamellocyte differentiation and melanotic tumour formation provide a convenient readout of inflammation and have been used to screen for modulators of inflammatory signaling pathways (Minakhina & Steward, 2006;Avet-Rochex et al, 2010).…”