Transcripts from the Drosophila heat-shock gene hsr-omega influence rates of protein synthesis but hardly affect resistance to heat knockdown

• Published in: Molecular genetics and genomics : MGG 2011-04, Vol.285 (4), p.313-323
• Main Authors: Johnson, Travis K, Cockerell, Fiona E, McKechnie, Stephen W
• Format: Article
• Language: English
• Subjects: Adaptation; Adaptation, Physiological - genetics; adults; Alleles; Animal Genetics and Genomics; Animals; Base Sequence; Biochemistry; Biomedical and Life Sciences; Cytoplasm; DNA Transposable Elements - genetics; Drosophila; Drosophila melanogaster - genetics; Gene Deletion; gene expression; Gene Expression Regulation; Genes; Genes, Insect - genetics; Genetic Loci - genetics; Genomics; heat; Heat resistance; Heat shock proteins; heat stress; heat tolerance; heat treatment; Heat-Shock Response - genetics; Hot Temperature; Human Genetics; Insects; Life Sciences; messenger RNA; Microbial Genetics and Genomics; Molecular Sequence Data; mutants; Mutation; Original Paper; Plant Genetics and Genomics; Protein Biosynthesis - genetics; Protein synthesis; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - genetics; RNA, Messenger - metabolism; Survival Analysis; viability
• ISSN: 1617-4615; 1617-4623
• DOI: 10.1007/s00438-011-0610-7

While hundreds of genes have recently been implicated in an organism's response to thermal stress, our insight into the cellular and physiological mechanisms affected by these genes has advanced to a lesser extent. We focus on an enigmatic Drosophila heat stress RNA gene, hsr-omega, which encodes two RNA transcripts that are constitutively expressed in almost all developing and adult tissues, omega-n in the nucleus and omega-c in the cytoplasm; both being readily induced to high levels by mild heat stress. We derived three hsr-omega mutant lines via imprecise P-element excision and characterised them for changes in expression, in both the presence and absence of heat stress. Viability estimates indicate that a low level of omega-n is required for normal development. Consistent with the model of omega-n as a negative regulator of intron-processed mRNA levels the mutants displayed a 1.5-fold increase in rates of protein synthesis measured in ovarian tissue in the absence of heat stress, a result suggesting that an important function of hsr-omega is the modulation of general protein synthesis. The mutants had little effect on two measures commonly used to assess heat tolerance, heat-knockdown time and heat hardening ability, suggesting that more subtle heat-related fitness components need to be examined for effects of these mutations.