Wild-type or dyf-7(m537) embryos expressing myristyl-GFP in most sensory neurons were imaged during the time of dendrite development. A pair of single focal planes (green and purple) spanning the depth of the amphid bundle are shown. The amphid bundle is marked (asterisk, cell bodies; arrowhead, dendritic tips) at the beginning and end of the series. In addition to the amphid bundle, a pair of cells adjacent to the amphid (purple focal plane) has shortened dendrites, and other sensilla exhibit possible defects.
Movie 1 [9.8 MB]
Dendrite formation in wild-type and dyf-7 embryos
Optical cell marking (OCM) was used to visualize the formation of a single dendrite in wild-type (Movies 1-4) or dyf-7(m537) (Movies 5-8) embryos. The cell of interest is boxed in the color image on the left and magnified 2.5x in the grayscale image on the right; scale bar applies to magnified box. Each time point is a maximum brightness projection of an optical stack ranging from 0.8 - 5.2 Ám thick. OCM signal in other cells is due to inadvertant photoconversion of neighboring cells or expression in some cells of such high levels of Kaede that even basal red fluorescence is comparable to the photoconverted signal within the cell of interest.
Movie 2 [13.8 MB] Movie 3 [7.9 MB] Movie 4 [11.9 MB] Movie 5 [16.5 MB]
Movie 6 [10.5 MB] Movie 7 [11.9 MB] Movie 8 [9.2 MB] Movie 9 [10.5 MB]
Timing of dex-1 and dyf-7 expression
Time-lapse series of an embryo bearing dex-1pro:myristyl-mCherry and dyf-7pro:myristyl-GFP transgenes. Each frame is a single focal plane. Images were collected under fixed exposure conditions and all time points were subjected to identical manipulations for brightness, contrast, and color. Expression initiates during bean stage (150-200 min in this series) just prior to dendrite formation. The ventral medial cell that brightly expresses both markers, appearing yellow, is the excretory cell.
Movie 10 [9.3 MB]
DYF-7-GFP localizes to dendritic tips during dendrite formation
Time-lapse images of an embryo bearing a dyf-7pro:dyf-7-GFP transgene reveal DYF-7-GFP at the presumptive dendritic tips (arrow) prior to and during the time when the neuronal cell bodies (asterisk) undergo the posterior migration that results in dendrite formation by retrograde extension. In addition to the punctate foci at dendritic tips, DYF-7-GFP signal was observed less intensely around the rest of the plasma membrane. The neurons of the amphid sense organ are annotated here; DYF-7-GFP is also visible here in what appear to be sensory neurons of the inner and outer labial sensilla in the head (top of embryo) and the phasmid sensilla in the tail (bottom-left region of embryo).
Movie 11 [2.3 MB]