Authors:

Annabel Pothuru

Date Created:

Not specified

Course Title:

Professor:

Not specified

About Paper:

During embryonic development, specification of ectodermal cells into the three ectodermal fates of the Neural Crest (NC), central nervous system (CNS) and skin (epidermis) is a crucial process for forming body structures. The NC forms the peripheral nervous system & craniofacial skeleton and develops between the CNS and epidermis [1]. These fates are separated into regions with defined boundaries, but disruptions can cause severe birth defects [2]. A complex regulatory network controls this specification but is incompletely understood; Snail family transcription factors (Snai 1/2) are good candidates for investigation of specification, since they regulate NC expression patterns at certain stages [1]. This study investigated the hypothesis that Snail factors regulate gene expression during ectodermal fate determination to separate the three initially overlapping regions. Using Xenopus laevis embryos as a model system, Snail activity was manipulated through knockdown (KD) and overexpression (OE) approaches through injection of dominant-negative constructs and Snai1/2 mRNA injections respectively. Embryos were injected at the two-cell stage to manipulate one side of the embryo and keep the uninjected side as an internal control. /n situ hybridization probes targeted marker genes for each fate, using foxd3 (NC), sox2 (CNS), and epik (epidermis) to visualize expression of these genes to compare changes in expression patterns between the manipulated and control sides. For the NC, KD decreased foxd3 expression and OE increased expression. For the CNS, KD caused an expansion of sox2 expression while OE reduced expression. While epik results were inconsistent, they can inform later research. Together, these results suggest that Snail transcription factors help create a defined boundary between the ectodermal fates by regulating genetic expression to simultaneously reduce specification into CNS and promote specification into NC. Ongoing work builds off these results, exploring how Snail factors regulate specification of cells directly in the boundaries between ectodermal fates.

Source:

Northwestern University

Topics:

No topics listed

Co-authors:

Annabel Pothuru