Evolution of the ventral midline in insect embryos

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Item Type:	Article
Title:	Evolution of the ventral midline in insect embryos
Creators Name:	Zinzen, R.P., Cande, J., Ronshaugen, M., Papatsenko, D. and Levine, M.
Abstract:	The ventral midline is a source of signals that pattern the nerve cord of insect embryos. In dipterans such as the fruitfly Drosophila melanogaster (D. mel.) and the mosquito Anopheles gambiae (A. gam.), the midline is narrow and spans just 1-2 cells. However, in the honeybee, Apis mellifera (A. mel.), the ventral midline is broad and encompasses 5-6 cells. slit and other midline-patterning genes display a corresponding expansion in expression. Evidence is presented that this difference is due to divergent cis regulation of the single-minded (sim) gene, which encodes a bHLH-PAS transcription factor essential for midline differentiation. sim is regulated by a combination of Notch signaling and a Twist (Twi) activator gradient in D. mel., but it is activated solely by Twi in A. mel. We suggest that the Twi-only mode of regulation--and the broad ventral midline--represents the ancestral form of CNS patterning in Holometabolous insects.
Keywords:	Basic Helix-Loop-Helix Transcription Factors, Biological Evolution, Body Patterning, Central Nervous System, Drosophila Proteins, Genetic Enhancer Elements, Genetic Transcription, Larva, Nonmammalian Embryo, Notch Receptors, Nuclear Proteins, Transgenes, Twist Transcription Factor, Animals, Anopheles gambiae, Bees, Drosophila melanogaster
Source:	Developmental Cell
ISSN:	1534-5807
Publisher:	Cell Press
Volume:	11
Number:	6
Page Range:	895-902
Date:	December 2006
Official Publication:	https://doi.org/10.1016/j.devcel.2006.10.012
PubMed:	View item in PubMed

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