Feeding-Related Traits Are Affected by Dosage of theforagingGene inDrosophila melanogaster

Abstract

Nutrient acquisition and energy storage are critical parts of achieving metabolic homeostasis. The foraging gene in Drosophila melanogaster has previously been implicated in multiple feeding-related and metabolic traits. Before foraging's functions can be further dissected, we need a precise genetic null mutant to definitively map its amorphic phenotypes. We used homologous recombination to precisely delete foraging, generating the for 0 null allele, and used recombineering to reintegrate a full copy of the gene, generating the {for BAC } rescue allele. We show that a total loss of foraging expression in larvae results in reduced larval path length and food intake behavior, while conversely showing an increase in triglyceride levels. Furthermore, varying foraging gene dosage demonstrates a linear dose-response on these phenotypes in relation to foraging gene expression levels. These experiments have unequivocally proven a causal, dose-dependent relationship between the foraging gene and its pleiotropic influence on these feeding-related traits. Our analysis of foraging's transcription start sites, termination sites, and splicing patterns using rapid amplification of cDNA ends (RACE) and full-length cDNA sequencing, revealed four independent promoters, pr1-4, that produce 21 transcripts with nine distinct open reading frames (ORFs). The use of alternative promoters and alternative splicing at the foraging locus creates diversity and flexibility in the regulation of gene expression, and ultimately function. Future studies will exploit these genetic tools to precisely dissect the isoform-and tissue-specific requirements of foraging's functions and shed light on the genetic control of feeding-related traits involved in energy homeostasis.

Epigenetic mechanisms modulate differences in Drosophila foraging behavior

“…for regulates various behavioral and physiological phenotypes in the fly and other organisms, including humans (4)(5)(6)(7)(8)(9). Importantly, this gene, with its rover and sitter allelic variants, is known to give rise to naturally occurring behavioral variations in D. melanogaster.…”

Distinct functions of a cGMP-dependent protein kinase in nerve terminal growth and synaptic vesicle cycling

“…Kinases can phosphorylate multiple targets, be expressed in different cells, have different subcellular expression patterns and be temporally activated at different times, all of which are means of pleiotropy. FOR has been implicated in behavioural pleiotropy (Allen et al, 2017;Anreiter et al, 2017;Allen et al, 2018;Anreiter and Sokolowski, 2018). Here, we show distinct spatial and temporal requirements for FOR at the synapse.…”

“…We expressed this BAC in a for null background. The C-terminus was tagged because it is common to all FOR isoforms (Allen et al, 2017;Fig. 1A).…”

“…Mid-third-instar larvae were used for all experiments. A sitter strain (+;+;+) was used as a wild-type control and all lines were backcrossed to it (Allen et al, 2017). The for 0 null mutant contains a 35 kb deletion that removes the entire for locus (Allen et al, 2017).…”

Drosophilaas a model to study obesity and metabolic disease

“…Conditional strategies have been used to rapidly identify specific regulators of obesity in a single gene or genes using various reverse genetics paradigms (exemplified by Lee et al, 2014;Pospisilik et al, 2010). Finally, knock-in by homologous recombination (Rong et al, 2002) and gene editing technologies such as transcription activator-like effector nucleases (TALENs) (Beumer et al, 2008) and clustered regularly interspaced short palindromic repeats (CRISPR) (Bassett et al, 2013;Gratz et al, 2013) allow in vivo genome editing with single base resolution and have been successfully employed in genetic studies of Drosophila obesity research (Allen et al, 2017;Gáliková et al, 2015;Sajwan et al, 2015).…”