The lens: a classical model of embryonic induction providing new insights into cell determination in early development

Abstract

The lens was the first tissue in which the concept of embryonic induction was demonstrated. For many years lens induction was thought to occur at the time the optic vesicle and lens placode came in contact. Since then, studies have revealed that lens placodal progenitor cells are specified already at gastrula stages, much earlier than previously believed, and independent of optic vesicle interactions. In this review, I will focus on how individual signalling molecules, in particular BMP, FGF, Wnt and Shh, regulate the initial specification of lens placodal cells and the progressive development of lens cells. I will discuss recent work that has shed light on the combination of signalling molecules and the molecular interactions that affect lens specification and proper lens formation. I will also discuss proposed tissue interactions important for lens development. A greater knowledge of the molecular interactions during lens induction is likely to have practical benefits in understanding the causes and consequences of lens diseases. Moreover, knowledge regarding lens induction is providing fundamental important insights into inductive processes in development in general.

The Orchestration of Mammalian Tissue Morphogenesis through a Series of Coherent Feed-forward Loops

“…Gene-To identify GRNs that control tissue morphogenesis, we used the lens as a model tissue (11), as its structure and function depends on a coordinated expression of 14 crystallin genes that is under the control of a small group of transcription factors, including Pax6 and c-Maf. To study transcriptional regulation of c-Maf in vivo, we performed a series of transgenic mouse studies.…”

Chromatin remodeling enzyme Snf2h regulates embryonic lens differentiation and denucleation

“…The lens vesicle is polarized. Its posterior cells exit the cell cycle in response to the BMP and FGF growth factors produced by the retina and ciliary body, and differentiate into the primary lens fiber cells (Griep and Zhang, 2004;Gunhaga, 2011). The anterior cells differentiate into a sheet of single-layered lens epithelial cells (Martinez and de Iongh, 2010).…”

The ocular lens: a classic model for development, physiology and disease

“…the role of specific growth factors and tissue interactions in developmental determination and patterning events) and these are providing fundamentally important insights into inductive processes in development in general. The article here by Lena Gunhaga addresses these issues, specifically focusing on how individual signalling molecules, including bone morphogenetic proteins (BMPs), fibroblast growth factors (FGFs), Wnts and Shh, regulate the initial specification of lens placodal cells and the progressive development of the lens via the coordination of both molecular and tissue interactions [3].…”