3D, time-lapse imaging of C. elegans embryogenesis
Movie shows the development of a C. elegans embryo from the 2-cell stage until it starts to twitch at 75s time interval, with histone::mCherry labeling all nuclei and PHA-4::GFP reporting PHA-4 expression (a gene expressed specifically in pharyngeal and gut cells). Each frame is a maximum projection of 30 Z stacks (1 micron apart) at a time point. Images were taken using a spinning disc confocal microscopy under 63X objective.
Digitization and single-cell analysis of embryogenesis by cell identification and tracing
Based on ubiquitously expressed histone::mCherry every cell produced during embryogenesis is identified and followed systematically to construct the cell lineage for an embryo. Cells are color coded according to lineage origins. Lineage tracing digitizes embryogenesis at the single-cell resolution and provides a framework to perform systematic phenotypic profiling of embryogenesis for individual cells. Ample information of embryogenesis such as gene expression, cell cycle, division pattern and position can be readily extracted to understand embryogenesis.
Large-scale analysis of gene function in cell fate choice and lineage differentiation
Movie shows 820 identified functions for 201 genes in early cell lineage differentiation. The syntax of gene functional annotation is "a gene regulates these aspects of lineage differentiation in this specific progenitor cell". Two types of regulatory role were identified: those that induced homeotic transformations are considered regulatory switches of binary cell fate choice; those that induced other abnormalities in lineage differentiation are considered as regulators of cell fate differentiation. In the movie, the standard cell lineage that leads to the 13 founder cells is represented as white nodes (cells) connected by black lines (mother-daughter relationship). Gene functions are mapped onto specific cells: red nodes represent cases of homeotic transformations with arrows representing the type and direction of fate transformation; blue nodes represent cases where the lineage differentiation in the sublineage of a given progenitor cell is affected by gene perturbation.