Proneural proteins Achaete and Scute associate with nuclear actin to promote external sensory organ formation

Abstract

Basic helix-loop-helix (bHLH) proneural proteins promote neurogenesis through transcriptional regulation. Although much is known about the tissue-specific regulation of proneural gene expression, how proneural proteins interact with transcriptional machinery to activate downstream target genes is less clear. Drosophila proneural proteins Achaete (Ac) and Scute (Sc) induce external sensory organ formation by activating neural precursor gene expression. Through co-immunoprecipitation and mass spectrometric analyses, we found that nuclear but not cytoplasmic actin associated with the Ac and Sc proteins in Drosophila S2 cells. Daughterless (Da), the common heterodimeric partner of Drosophila bHLH proteins, was observed to associate with nuclear actin through proneural proteins. A yeast two-hybrid assay revealed that the binding specificity between actin and Ac or Sc was conserved in yeast nuclei without the presence of additional Drosophila factors. We further show that actin is required in external sensory organ formation. Reduction in actin gene activity impaired proneural-protein-dependent expression of the neural precursor genes, as well as formation of neural precursors. Furthermore, increased nuclear actin levels, obtained by expression of nucleus-localized actin, elevated Ac-Da-dependent gene transcription as well as Ac-mediated external sensory organ formation. Taken together, our in vivo and in vitro observations suggest a novel link for actin in proneural-protein-mediated transcriptional activation and neural precursor differentiation.

Reproduction disrupts stem cell homeostasis in testes of aged male Drosophila via an induced microenvironment

“…The amount of target RNA was normalized to the reference gene rp49 . PCRs were performed using the following pairs of primers: rp49 , 5’-ATCGG TTACG GATCG AACAA-3’ and 5’-GACAA TCTCC TTGCG CTTCT-3’ [117]. egr , 5’-TCGTC GATAA TCTCC AGCAG-3’ and 5’-GGATA GTCGA TGAGG GCATT-3’; and grnd , 5’-ACTAC GATGC CTTTC TGTGC-3’ and 5’-AGGAT CAGCT GCTGG GTATT-3’.…”

Actin blobs prefigure dendrite branching sites

“…The GFP trap tsr line tsr CPTI002237 (115280; Grintsevich et al, 2016 ) was from Kyoto Stock Center. Other transgenes used were UAS-Jupiter-mCherry ( Cabernard and Doe, 2009 ), UAS-myc-Actin G15S , and UAS-myc-Act42A ( Hsiao et al, 2014 ). UAS-LifeAct-GFP (35544; Hatan et al, 2011 ), UAS-LifeAct-RFP (58362; Cai et al, 2014 ), UAS-Kat60 (64115; Mao et al, 2014 ), and UAS-GMA (31775 and 31774; Kiehart et al, 2000 ) were obtained from BDSC.…”

A Multivariate Genome-Wide Association Study of Wing Shape inDrosophila melanogaster

“…Proteins coded for by kuz and mam physically and genetically interact with the N pathway (Qi et al 1999;Petcherski and Kimble 2000;Dornier et al 2012;Yuan et al 2016;Gramates et al 2017). Actin interacts physically with the achaete-scute complex proteins (Hsiao et al 2014), which then signal neighboring cells through the N pathway (Heitzler et al 1996). While a SNP in the intron of N was significant in our initial GWAS, it did not survive in the LASSO analysis (its effect shrank down to zero).…”