The Gcm/Glide molecular and cellular pathway: New actors and new lineages

Abstract

In Drosophila, the transcription factor Gcm/Glide plays a key role in cell fate determination and cellular differentiation. In light of its crucial biological impact, major efforts have been put for analyzing its properties as master regulator, from both structural and functional points of view. However, the lack of efficient antibodies specific to the Gcm/Glide protein precluded thorough analyses of its regulation and activity in vivo. In order to relieve such restraints, we designed an epitope-tagging approach to "FLAG"-recognize and analyze the functional protein both in vitro (exogenous Gcm/Glide) and in vivo (endogenous protein). We here (i) reveal a tight interconnection between the small RNA and the Gcm/Glide pathways. AGO1 and miR-1 are Gcm/Glide targets whereas miR-279 negatively controls Gcm/Glide expression (ii) identify a novel cell population, peritracheal cells, expressing and requiring Gcm/Glide. Peritracheal cells are non-neuronal neurosecretory cells that are essential in ecdysis. In addition to emphasizing the importance of following the distribution and the activity of endogenous proteins in vivo, this study provides new insights and a novel frame to understand the Gcm/Glide biology.

Interlocked loops trigger lineage specification and stable fates in the Drosophila nervous system

“…Interestingly, Gcm and Repo boost their own expression on autoregulation 4,12 and transiently coexist 2,3,9,10,13,14 . Thus, we hypothesized that Repo acts as a molecular relay, regulating the threshold and dynamic accumulation of Gcm that is necessary for gliogenesis.…”

Revisiting the role of the Gcm transcription factor, from master regulator to Swiss army knife

“…1C and D). [12][13][14][15][16][17] Importantly, in these tissues, the gene is expressed in the differentiated cells, as opposed to the transient and early expression observed in glia and in hemocytes, already suggesting that the so-called master genes may have distinct roles depending on the cell type. In tendon cells, Gcm is necessary for their function/terminal differentiation.…”

“…18,19 In the trachea, gcm is expressed in the peritracheal secretory cells called INKA cells. 17 The INKA cells secrete the ecdysis-triggering hormone and participate to the control of ecdysial behaviors. 20 gcm LOF animals are devoid of INKA cells.…”

Enhanced Northern Blot Detection of Small RNA Species in <em>Drosophila Melanogaster</em>

“…Drosophila miRNAs have revealed distinct functions in insect-specific or evolutionarily conserved processes, spanning from aging to metabolism, signaling pathways, behavior and, of course, neurogenesis. Along this direction, we recently unveiled a novel link 16 in the intriguing correlation occurring between the master gene gcm/glide and the RNA pathway. The fly transcription factor Gcm/Glide [17][18][19] constitutes a unique example of cell fate determinant, which dictates the glial vs. neuronal fate choice in multipotent fly neural precursors 20 .…”

“…We discovered that regulation via Dmel-miR279 targeting represents a further control level contributing to post-transcriptional fine-tuning of gcm/glide expression 16 . Globally, these research lines have required specific methodological improvements: along years, several technologies originally developed to analyze traditional RNAs have been converted for quantifying small non coding RNAs, like as RNAse protection assays, cDNA arrays [29][30][31] , real-time PCR methods [32][33][34][35] and sequencing 36,37 .…”