Transcriptomic Analysis of the Spatiotemporal Axis of Oogenesis and Fertilization in C. elegans
The oocyte germline of the C. elegans hermaphrodite presents a unique model to study the formation of oocytes. However, the size of the model animal and difficulties in retrieval of specific stages of the germline have obviated closer systematic studies of this process throughout the years. Here, we present a transcriptomic level analysis into the oogenesis of C. elegans hermaphrodites. We dissected a hermaphrodite gonad into seven sections corresponding to the mitotic distal region, the pachytene, the diplotene, the early diakinesis region and the 3 most proximal oocytes, and deeply sequenced the transcriptome of each of them along with that of the fertilized egg using a single-cell RNA-seq protocol. We identified specific gene expression events as well as gene splicing events in finer detail along the oocyte germline and provided novel insights into underlying mechanisms of the oogenesis process. These results expand our knowledge of the transcriptomic space of the C. elegans germline and lay a foundation on which future studies of the germline can be based upon. Overall design: we combined microdissection with scRNA-seq technique, and profiled the transcriptomes in the proliferative zone, pachytene zone, diplotene zone, early diakinesis zone (before -3 oocyte stage), later diakinesis zone (-3, -2, -1 oocytes), and the zygote. We identified not only many genes that were known to play roles in oogenesis and fertilization, but also many novel candidate genes that may be significant in each of the stages.