Non-coding RNAs demystify constitutive heterochromatin as essential modulator of epigenotype

Altered levels ofhsromegalncRNAs further enhance Ras signaling during ectopically activated Ras induced R7 differentiation inDrosophila

“…Since the hsrω transcripts are not known to bind with gene promoters or other RNAs, the changes in activities of the above noted negative and positive modulators of Ras signaling appears to be related to changes in activities of the diverse proteins that associate with these lncRNAs. Of the multiple transcripts produced by hsrω gene (Lakhotia, 2011;Lakhotia, 2017b), the >10kb nucleus-limited transcripts are essential for biogenesis of the omega speckles and consequently for the dynamic movement of the omega speckle associated proteins like various hnRNPs, certain other RNA binding proteins and some nuclear matrix proteins etc (Lakhotia et al, 2012;Mallik and Lakhotia, 2011;Piccolo et al, 2018;Piccolo and Yamaguchi, 2017;Singh and Lakhotia, 2015). The GAL4 induced expression of hsrωRNAi transgene or of the EP3037 allele of hsrω is known to primarily lower and elevate, respectively, levels of the larger and nucleus-limited transcripts of hsrω gene (Mallik and Lakhotia, 2009) .…”

“…Evolution of multi-cellularity and the associated division of labour between different cell types has necessitated inter-cellular signaling pathways with complex network of regulatory circuits. The evolution of biological complexity has also been paralleled by substantial increase in the non-coding component in diverse genomes, and there is increasing realization in recent years that the large varieties of short and long non-coding RNAs (lncRNA) have great roles in cell signaling and gene regulation (Geisler and Coller, 2013;Huang et al, 2013;Jose, 2015;Lakhotia, 2016;Lakhotia, 2017a;Lakhotia, 2017b;Mattick and Makunin, 2006;Morris and Mattick, 2014;Peng et al, 2017). The lncRNAs like acal, mrhl, CRNDE, LncND, and URHC have been reported to regulate JNK, Wnt, insulin, Notch and ERK/MAPK signaling pathways, respectively (Arun et al, 2012;Ellis et al, 2014;Katsushima et al, 2016;Ríos-Barrera et al, 2015;Xu et al, 2014).…”

“…The lncRNAs like acal, mrhl, CRNDE, LncND, and URHC have been reported to regulate JNK, Wnt, insulin, Notch and ERK/MAPK signaling pathways, respectively (Arun et al, 2012;Ellis et al, 2014;Katsushima et al, 2016;Ríos-Barrera et al, 2015;Xu et al, 2014). Besides their roles in developmental regulation (Katsushima et al, 2016;Kotake et al, 2016;Lakhotia, 2017b;Misawa et al, 2017;Zhang et al, 2017a), diverse lncRNAs have been reported to interact with components of the various signaling pathways in cancer, activating or repressing their strength and thus affecting outcomes like cell proliferation or apoptosis (Lakhotia, 2016;Liu et al, 2015;Wang et al, 2015). An earlier study (Ray and Lakhotia, 1998) from our laboratory showed that mutant alleles of ras (ras E62K and ras D38N ) dominantly enhanced the lethality due to nullisomic condition of the hsrω gene, which produces multiple lncRNAs (Lakhotia, 2011;Lakhotia, 2017a).…”

Heterochromatic hues of transcription—the diverse roles of noncoding transcripts from constitutive heterochromatin

“…As we move up the evolutionary ladder, in invertebrates like Drosophila, ncRNAs have been shown to play a crucial role in various aspects of constitutive heterochromatin biology (reviewed in Ref. ). These transcripts, generated by RNA Pol II and RNAi machinery components ( Dicer, Ago1‐2, Aubergine ), interact to maintain the heterochromatic state (Fig.…”