A model study of the morphogenesis ofD. melanogastermechanoreceptors: The central regulatory circuit

Abstract

Macrochaetes (large bristles) are sensor organs of the Drosophila peripheral nervous system with a function of mechanoreceptors. An adult mechanoreceptor comprises four specialized cells: shaft (trichogen), socket (tormogen), neuron, and glial cell (thecogen). All these cells originate from a single cell, the so-called sensor organ precursor (SOP) cell. Separation of the SOP cell from the encompassing cells of the imaginal disc initiates a multistage process of sensory organ development. A characteristic feature of the SOP cell is the highest amount of the proneural proteins AS-C as compared with the encompassing ectodermal cells. The accumulation of proneural proteins and maintenance of their amount in the SOP cell at a necessary level is provided by the gene network with the achaete-scute gene complex (AS-C) as its key component. The activity of this complex is controlled by the central regulatory circuit (CRC). The CRC comprises the genes hairy, senseless (sens), charlatan (chn), scratch (scrt), daughterless (da), extramacrochaete (emc), and groucho (gro), coding for the transcription factors involved in the system of direct links and feedbacks and implementation of activation-repression relationships between the CRC components. The gene phyllopod (phyl), involved in degradation of the AS-C proteins, is also associated with the CRC functioning. In this paper, we propose a mathematical model for the CRC functioning as a regulator of the amount of proneural AS-C proteins in the SOP cell taking into account their degradation. The modeling has demonstrated that a change in the amount of proneural proteins in the SOP cell is stepwise rather than strictly monotonic. This prediction can be tested experimentally.

The human olfactory transcriptome

“…Of these we note the gene ASCL3, member of the achaete-scute complex (ASC) family which has a role in cell fate determination and differentiation of numerous tissues, including neuronal tissues [ 36 ]. In drosophila achaete-scute gene complex (AS-C) is a key component in developing of the macrochaetes sensory organs [ 37 ]. The paralog ASCL1 is required for early development of olfactory neuron [ 38 ].…”

The central regulatory circuit in the gene network controlling the morphogenesis of Drosophila mechanoreceptors: an <i>in silico</i> analysis

“…Green arrows show activator effects (solid line, direct and dashed, mediated) and red arrows with chopped ends denote repressor effects (solid line, direct and dashed, mediated). The earlier published scheme (Golubyatnikov et al, 2015) has been updated by adding the ASC protein degradation system. constituent genes that would comprehensively describe the intracellular events in presumptive SOPC determining the dynamics of ASC content and to perform the computer ex periments for verifying the model stability and its compliance with experimental data.…”

Long noncoding RNASMRGregulatesDrosophilamacrochaetes by antagonizingscutethrough E(spl)mβ

“…Macrochaetes (large bristles) are sensory organs of the Drosophila peripheral nervous system, acting as external mechanoreceptors [15]. The number and location of macrochaetes are strictly constant, and the pattern they form is species-specific in Drosophila [16,17].…”

“…Each mechanoreceptor contains four specialized cells: trichogen (shaft), tormogen (socket), neuron, and thecogen (glial cell). All of these cells are produced by a single cell, the so-called sensor organ precursor (SOP) cell [22].The main feature of the SOP cell compared with the encompassing cells lies in the maximal amount of AS-C proteins, produced by the achaete-scute gene complex (AS-C) [15]. AS-C is composed of four proneural genes, achaete (ac), scute (sc), lethal of scute (l'sc), and asense (ase), encoding transcription factors of the Class II bHLH family [23].…”