499C Poster - 06. Regulation of gene expression
Saturday April 09, 1:30 PM - 3:30 PM

Pleiotropic fitness effects at the Uhg4-Boot locus in Drosophila melanogaster


Authors:
Rebecca A MacPherson 1,2; Robert R. H. Anholt 1,2; Trudy F. C. Mackay 1,2

Affiliations:
1) Center for Human Genetics, Clemson University, Greenwood, SC; 2) Department of Genetics and Biochemistry, Clemson University, Greenwood, SC

Keywords:
l. non-coding RNAs; i. non-coding RNAs

U snoRNA host gene 4 (Uhg4) encodes an antisense long noncoding RNA that is moderately expressed throughout the fly, with highest expression in embryos and adult ovaries. Uhg4 is host to seven small nucleolar RNAs (snoRNAs) and is coregulated with a subset of 37 snoRNAs that are differentially regulated in a background-dependent manner in females in response to developmental ethanol exposure. Bootlegger (Boot) is immediately upstream of and in opposite orientation to Uhg4 and encodes a protein critical for nuclear export of noncoding piwi-interacting RNAs. Expression of Boot is almost exclusively confined to ovaries. We have generated multiple deletions spanning the first exon of Uhg4 and the promotor regions of both Boot and Uhg4 using CRISPR-Cas9 and revealed a spectrum of pleiotropic effects on fitness traits, including increased development time, changes to sleep and stress response, background-dependent decreases in viability, as well as sterility in both sexes. RNA sequencing data suggest that the region between Uhg4 and Boot is required for normal expression of Uhg4, two intronic snoRNAs hosted by Uhg4, as well as Boot, leading to 668 differentially expressed genes. Gene ontology enrichment analysis showed enrichment of genes involved in immune response, ribosome formation, and DNA repair. We compared CRISPR-Cas9 deletion mutants of the Boot-Uhg4 regulatory region with RNAi-mediated knockdown of Boot and found that many of the effects on organismal phenotypes can be attributed both to Boot and the lncRNA Uhg4. However, we also observe differences in sexual dimorphism as well as antagonistic effects on fitness traits due to disruption of these genes. Thus, this regulatory region in the Drosophila genome highlights a long noncoding RNA and a protein coding gene that are both essential for reproduction and fitness.