Pleiotropic consequences of misexpression of the developmentally active and stress-inducible non-coding hsrω gene in Drosophila.
Date
2011-06
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Abstract
The non-coding hsrω gene of Drosophila melanogaster is expressed in nearly all cell types and developmental
stages. However, in the absence of conventional mutant alleles of this gene, its developmental functions remain
largely unknown. In the present study, we used a variety of GAL4 drivers to overexpress or ablate this gene’s
transcripts in specific tissues and examined the developmental consequences thereof. Our results show that a
balanced expression of these non-coding transcripts is critical for survival and normal development in all the tissue
types tested, since any change in cellular levels of these transcripts in a given cell type generally has detrimental
effects, with extreme cases resulting in organismal lethality, although in a few cases the misexpression of these
transcripts also suppresses the mutant phenotype due to other genetic conditions. Evidence is also presented for
existence of a new spliced variant of the hsrω-n nuclear transcript. Following the RNAi-mediated down-regulation of
hsrω transcripts, the omega speckles disappear so that the nucleoplasmic hnRNPs get diffusely distributed, while upregulation
of these transcripts results in greater sequestration of these proteins into omega speckle clusters; either of
these conditions would affect activities of the hnRNPs and other hsrω-RNA interacting proteins, which is likely to
have cascading consequences. The present findings, together with our earlier observations on effects of altered levels
of the hsrω transcripts on induced apoptosis and expanded polyQ-mediated neurodegeneration, further confirm that
ncRNA species like the hsrω, far from being evolutionary hangovers, provide critical information for important
functions in normal cells.
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Keywords
EP, hnRNPs, Hrb87F, hsrω, lamin C, non-coding RNA, omega speckles, RNAi
Citation
Mallik Moushami, Lakhotia Subhash C. Pleiotropic consequences of misexpression of the developmentally active and stress-inducible non-coding hsrω gene in Drosophila. Journal of Biosciences. 2011 Jun; 36(2): 265-280.