Deconstructing the complexity of regulating common properties in different cell types: Lessons from the delilah gene

Abstract

To understand development we need to understand how transcriptional regulatory mechanisms are employed to confer different cell types with their unique properties. Nonetheless it is also critical to understand how such mechanisms are used to confer different cell types with common cellular properties, such as the ability to adhere to the extracellular matrix. To decode how adhesion is regulated in cells stemming from different pedigrees we analyzed the regulatory region that drives the expression of Dei, which is a transcription factor that serves as a central determinant of cell adhesion, particularly by inducing expression of βPS-integrin. We show that activation of dei transcription is mediated through multiple cis regulatory modules, each driving transcription in a spatially and temporally restricted fashion. Thus the dei gene provides a molecular platform through which cell adhesion can be regulated at the transcriptional level in different cellular milieus. Moreover, we show that these regulatory modules respond, often directly, to central regulators of cell identity in each of the dei-expressing cell types, such as D-Mef2 in muscle cells, Stripe in tendon cells and Blistered in wing intervein cells. These findings suggest that the acquirement of common cellular properties shared by different cell types is embedded within the unique differentiation program dictated to each of these cells by the major determinants of its identity.

An RNAi Screen Identifies New Genes Required for Normal Morphogenesis of Larval Chordotonal Organs

“…To overcome this limitation, we took advantage of recently developed ChO-specific fluorescent reporters that allow rapid screening of whole-mount larvae without any need for dissection or immuno-staining ( Halachmi et al 2016 ). These reporter constructs are based on cis -regulatory modules from the dei locus ( Nachman et al 2015 ) that were used for driving cytoplasmic GFP expression in the cap and ligament cells of ChOs ( dei ChO -GFP ), and cytoplasmic RFP in the attachment cells of ChOs ( dei attachment -RFP ) ( Figure 1C ). For the screening procedure the dei ChO -GFP , dei attachment -RFP chromosome was recombined to ato-Gal4 , which drives expression specifically in the LCh5 lineage, and to en-gal4 , which drives earlier and prolonged expression in the entire posterior compartment of the segment, including the LCh5 organs.…”

“…Primary antibodies used in this study: Rabbit anti-Dei (1:50; Egoz-Matia et al 2011), rabbit anti-αTub85E (1:50; Klein et al , 2010 ) and mouse anti-αTub85E (1:5;( Nachman et al 2015 ), mouse anti-Blistered/DSRF (1:00, a kind gift from S. Blair), MAb21A6 (1:20) was obtained from the Developmental Studies Hybridoma Bank, created by the NICHD of the NIH and maintained at the University of Iowa. Secondary antibodies for fluorescent staining were Cy3, or Alexa 647-conjugated anti-mouse or anti-rabbit antibodies (Jackson ImmunoResearch Laboratories, USA).…”

delilah, prosperoandD-Pax2constitute a gene regulatory network essential for the development of functional proprioceptors

“…To reveal the gene network that regulates dei expression in the ChO cells we used the ChO-specific dei ChO-1353 enhancer as an entry point. We first mapped the critical regulatory region within the dei ChO-1353 enhancer to a 389 bp fragment ( dei ChO-389 ) that accurately recapitulated the expression pattern of the full dei ChO-1353 enhancer (Nachman et al, 2015) (Figure 1D, F-G). Subsequently, we narrowed down the critical regulatory region to an evolutionarily conserved 262 bp fragment dei ChO-262 , which drives ChO-specific expression in a pattern indistinguishable from the expression pattern driven by the larger fragments dei ChO-1353 and dei ChO-389 (Figure 1D, F, H).…”

“…Even though dei is expressed in all four accessory cells, its expression in these cells is differentially regulated. The transcription of dei in the ChO is controlled by two cis -regulatory modules (CRMs): The dei attachment enhancer, located ~2.5Kb upstream of the dei transcription start site, drives expression in the cap-attachment and ligament-attachment cells (as well as tendon cells), whereas the dei ChO-1353 enhancer, an intronic 1353bp DNA fragment, drives dei expression specifically in the cap and ligament cells (Nachman et al, 2015) (Figure 1D-F). The dei attachment enhancer was shown to be activated by the transcription factor Stripe, which is considered a key regulator of tendon cell development (Becker et al, 1997) and a known determinant of attachment cell identity (Klein et al, 2010).…”

A Genome-Wide Identification and Analysis of the Basic Helix-Loop-Helix Transcription Factors in Brown Planthopper, Nilaparvata lugens

“…This group include proteins such as 48-related-1/Fer1, 48-related-2/Fer2, PTFa/Fer3, ASCa, ASCb, ASCc, amber, Atonal 2, Beta3, Delilah, E12/E47, Hand, Mesp, Mist, MyoD, MyoRa, MyoRb, Net, NeuroD, Neurogenin, NSCL, Oligo, paraxis, peridot, SCL and Twist families [15,57]. These proteins mainly regulate neurogenesis, myogenesis and mesoderm formation [58,59,60,61,62,63]. Our analysis shows that most of NlbHLH members exhibit 1:1 orthology with D. melanogaster , suggesting functional conservation.…”