Arsenal: Volume 1, Issue 2
Studying Gene Expression in Whole Embryos by in situ Hybridization: A Peer-to-Peer Laboratory GuideThe extracellular matrix (ECM) plays an important role in cell to cell signaling pathways. Our goal is to provide a full laboratory guide for students to study gene expression in zebrafish embryos by in situ hybridization. Prior to our study, the laboratory had observed disorganized and shortened cilia in cells that are important for cell signaling in the pronephric duct and neural tube floor plate of the zebrafish embryo. Ciliogenesis depends on a master transcriptional regulator, foxj1a, whose mRNA expression can be monitored through in situ hybridization and microscopic imaging. Knockdown morpholino-injected, control mismatched morpholino-injected, and uninjected embryos were fixed to determine if foxj1a transcription is qualitatively affected by ECM gene knockdown. Our results showed that the knockdown embryos portrayed an inconsistent foxj1a signal strength along the length of the pronephric duct, when compared to analysis of control mismatched and wild-type uninjected embryos. We created this manuscript for other students to observe how ECM gene knockdown can affect foxj1a mRNA expression, but also to give them a guide to the tools they would need to explore their own genes of interest, in zebrafish or in many other organisms and tissues.
Techniques Used to Establish the First Person Narrator and Perspective in Double Indemnity and Murder, My SweetDirected by Billy Wilder and Edward Dmytryk respectively, the films noir Double Indemnity (1944) and Murder, My Sweet (1944) each have a storyline that unfolds from a first person perspective as told by a narrator. The techniques used in the films establish this first person perspective through which the films are understood. Both films include voice over as a technique, which determines who the narrator is and the amount of information withheld or disclosed to the audience. Establishing the visual perspective of the narrator is portrayed through differently for each film. While, Double Indemnity utilizes camera angle, Murder, My Sweet uses camera filters and special effects. Lastly, to achieve the first person narration, the character narrating in each film must be present in every scene or give explanation of events that occur in his absence. The various techniques used in each film function cohesively to establish the narrator and achieve his perspective through which the plot is understood by the audience.