[
Sex Dev,
2023]
The nematode, Caenorhabiditis elegans has proven itself as a valuable model for investigating metazoan biology. Key features including a transparent body, an invariant cell lineage, ease of genetic manipulation, coupled with a high level of genetic conservation with higher eukaryotes make C. elegans a desierable model organism. Although used to elucidate many aspects of somatic biology, a distinct advantage of C. elegans is its well annotated germline which allows all aspects of oogenesis to be observed in real-time within a single animal. C. elegans hermaphrodites have two large germlines which produce their own sperm that is later stored to fertilize their own oocytes. These two germlines take up much of the internal space of each animal and therefore, germ cells are the most abundant cell present within each animal. This feature has allowed many novel findings that established early understanding of germ cell dynamics, as well as key features of meiosis and germ cell maturation to be unveiled. This review will focus on the key features that make C. elegans an outstanding model for exploring each feature of oogenesis. This will include the fundamental steps associated with germ line function and germ cell maturation and will be of use for those interested in exploring reproductive metazoan biology.
[
Parasitol Today,
1996]
Spliced leader trans-splicing is a form of RNA processing originally described and studied in parasitic kinetoplastida. This mechanism of gene expression also occurs in parasitic and free-living metazoa. In this review, Dick Davis describes current knowledge of the distribution, substrates, specificity and functional significance of trans-splicing in metazoa.
[
Exp Gerontol,
2006]
In Caenorhabditis elegans, the insulin/IGF-1 signaling pathway controls many biological processes such as life span, fat storage, dauer diapause, reproduction and stress response . This pathway is comprised of many genes including the insulin/IGF-1 receptor (DAF-2) that signals through a conserved PI 3-kinase/AKT pathway and ultimately down-regulates DAF-16, a forkhead transcription factor (FOXO). DAF-16 also receives input from several other pathways that regulate life span such as the germline and the JNK pathway [Hsin, H., Kenyon, C., 1999. Signals from the reproductive system regulate the lifespan of C. elegans. Nature 399, 362-366; Oh, S.W., Mukhopadhyay, A., Svrzikapa, N., Jiang, F., Davis, R.J., Tissenbaum, H.A., 2005. JNK regulates lifespan in Caenorhabditis elegans by modulating nuclear translocation of forkhead transcription factor/DAF-16. Proc. Natl. Acad. Sci. USA 102, 4494-4499]. Therefore, DAF-16 integrates signals from multiple pathways and regulates its downstream target genes to control diverse processes. Here, we discuss the signals to and from DAF-16, with a focus on life span regulation.