Editorial highlights

Abstract

Every organism is a model organism for understanding development, evolution, disease, and regeneration, and we have only begun to scratch the surface of the interdisciplinary genetic, molecular, cellular, and developmental mechanisms that regulate these biological processes. These “Highlights” denote exciting advances recently reported in Developmental Dynamics that illustrate the complex dynamics of developmental biology.

Cardiovascular Organogenesis. “Experimental Assessment of Cardiovascular Physiology in the Chick Embryo” by Vijayakumar Sukumaran, Onur Mutlu, Mohammad Murtaza, Rawia Alhalbouni, Benjamin Dubansky and Huseyin Yalcin; DevDyn 252:10, pp. 1247-1268; https://doi.org/10.1002/dvdy.589. Cardiovascular disease is a major cause of mortality. As soon as heart begins contracting during embryogenesis, the hemodynamic forces of blood moving through the heart and vasculature, helps drive and shape drive cardiac morphogenesis, angiogenesis, and development of the cardiac conduction system. Historically, the chicken embryo has served as an important model for cardiovascular research. This review article discusses several technical approaches for studying chick embryo cardiovascular development and physiology such as doppler echocardiography, optical coherence tomography, micro-magnetic resonance imaging, micro-particle image velocimetry, and real-time pressure monitoring, alongside recent advances in the measurement of cardiac function.

Hearing and Balance. “Fgf, Hh and pax2a differentially regulate expression of pax5 and pou3f3b in vestibular and auditory maculae in the zebrafish otic vesicle” by Amy Tan, Sydney Christensen, Allison Baker and Bruce Riley; DevDyn 252:10, pp. 1269-1279; https://doi.org/10.1002/dvdy.599. The vertebrate inner ear contains distinct sensory epithelia specialized for auditory or vestibular function. In zebrafish, utricular and saccular maculae alone mediate vestibular and auditory functions, respectively. Specification of utricular versus saccular maculae requires different levels of Fgf and Hh signaling, and alterations in combinatorial Fgf or Hh signaling elicit corresponding shifts in utricular vs. saccular development. However, pax2a maintains both fates downstream of these signaling pathways, and similarities in mouse embryos suggest this is indicative of a broadly conserved developmental mechanism.

Craniofacial and Tooth Development. “Enam expression is regulated by Msx2” by Intan Ruspita, Pragnya Das, Keiko Miyoshi, Takafumi Noma, Malcolm Snead and Marianna Bei; DevDyn 252:10, pp. 1292-1302; https://doi.org/10.1002/dvdy.598. Amelogenesis, the process of enamel formation, requires tight transcriptional control of secreted matrix proteins. Enamelin is one of the major proteins secreted by ameloblasts for propoper enamel formation. This study shows that expression of the Enam gene, which encodes enamalin, is regulated by Msx2. Another craniofacial study titled “Transcriptomic analysis reveals the role of Six1 in mouse cranial neural crest cell patterning and bone development” by Aparna Baxi, Karyn Jourdeuil, Timothy Cox, David Clouthier, and Andre Tavares; DevDyn 252:10, pp. 1303-1315; https://doi.org/10.1002/dvdy.597, set out to define the transcriptional network governed by Six1. Genetic variants in SIX1 can cause Branchio-oto-renal (BOR) syndrome and transcriptional profiling of Six1 mutant mouse embryos identified numerous differentially expressed genes involved in translation, neural crest cell differentiation, osteogenesis, chondrogenesis and Wnt signaling with implications for BOR syndrome disease pathogenesis.