-
[
Curr Opin Genet Dev,
1991]
This review addresses the role of cell-cell interactions in the development of the Caenorhabditis elegans germ line: specifically, the relative contributions of germ-line-soma interactions versus autonomous processes are considered. Current knowledge of the interacting cell types and the genes essential for various aspects of germ-line development is discussed.
-
[
Seminars in Developmental Biology,
1992]
The nematode Caenorhabditis elegans has two natural sexes, the self-fertilizing hermaphrodite (essentially a modified female) and the male. Sex is determined by X chromosome dosage: hermaphrodites are XX, males are XO. This primary signal sets the state of activity for a series of regulatory genes, which are organized hierarchically. The genes at the top of the hierarchy control both sex and dosage compensation; genes acting lower down in the hierarchy control sexual phenotype in both soma and germ-line, but do not affect dosage compensation. Regulation of sexual phenotype is somewhat different between soma and germ line. Many of the genes involved in sex determination have been subjected to molecular analyses. The results indicate that some of the regulatory interactions involve transcriptional controls and others
-
[
Development,
1999]
One hundred years after Weismann's seminal observations, the mechanisms that distinguish the germline from the soma still remain poorly understood. This review describes recent studies in Caenorhabditis elegans, which suggest that germ cells utilize unique mechanisms to regulate gene expression. In particular, mechanisms that repress the production of mRNAs appear to be essential to maintain germ cell fate and viability.
-
[
Curr Opin Genet Dev,
2003]
Recent studies in Caenorhabditis elegans implicate PcG- and NuRD-like chromatin regulators in the establishment and maintenance of germline-soma distinctions. Somatic cells appear to utilize NuRD-related nucleosome-remodeling factors to overwrite germline-specific chromatin states that are specified through PcG-like activities. The germline, in turn, may rely on an asymmetrically inherited inhibitor to prevent chromatin reorganization that would otherwise erase pluripotency.
-
[
Seminars in Developmental Biology,
1994]
Germ cell development in Caenorhabditis elegans involves three processes a shift from the mitotic to the meiotic cell cycle; the adoption of a male or female sexual identity; and differentiation into a functional gamete. All three aspects of germline development appear to be regulated, at least in part, by the soma. We discuss cell ablation, genetic and molecular studies that have shed light on the nature of the signal transduction systems mediating intracellular communication between germline and somatic tissues of the nematode.
-
[
Science,
2007]
The early embryo is formed by the fusion of two germ cells that must generate not only all of the nonreproductive somatic cell types of its body but also the germ cells for the next generation. Therefore, embryo cells face a crucial decision: whether to develop as germ or soma. How is this fundamental decision made and germ cell fate maintained during development? Studies in the nematode worm Caenorhabditis elegans and fruit fly Drosophila identify some of the decision-making strategies, including segregation of a specialized germ plasm and global transcriptional regulation.
-
[
Front Mol Biosci,
2015]
Experimental interventions that reduce reproduction cause an extension in lifespan. In invertebrates, such as Caenorhabditis elegans, the aging of the soma is regulated by signals from the germline. Indeed, ablation of germ cells significantly extends lifespan. Notably, germline-deficient animals exhibit heightened resistance to proteotoxic stress. This phenotype correlates with increased potential of intracellular clearance mechanisms such as the proteasome and autophagy in somatic tissues. Here we review the molecular mechanisms by which signals from the germline regulate lifespan in C. elegans with special emphasis on clearance mechanisms.
-
[
Wiley Interdiscip Rev Dev Biol,
2014]
Studies of the development of the Caenorhabditis elegans male have been carried out with the aim of understanding the basis of sexual dimorphism. Postembryonic development of the two C. elegans sexes differs extensively. Development along either the hermaphrodite or male pathway is specified initially by the X to autosome ratio. The regulatory events initiated by this ratio include a male-determining paracrine intercellular signal. Expression of this signal leads to different consequences in three regions of the body: the nongonadal soma, the somatic parts of the gonad, and the germ line. In the nongonadal soma, activity of the key Zn-finger transcription factor TRA-1 determines hermaphrodite development; in its absence, the male pathway is followed. Only a few genes directly regulated by TRA-1 are currently known, including members of the evolutionarily conserved, male-determining DM domain Zn-finger transcription factors. In the somatic parts of the gonad and germ line, absence of TRA-1 activity is not sufficient for full expression of the male pathway. Several additional transcription factors involved have been identified. In the germ line, regulatory genes for sperm development that act at the level of RNA in the cytoplasm play a prominent role.
-
[
Cell Mol Life Sci,
1999]
In all animals information is passed from parent to offspring via the germline, which segregates from the soma early in development and undergoes a complex developmental program to give rise to the adult gametes. Many aspects of germline development have been conserved throughout the animal kingdom. Here we review the unique properties of germ cells, the initial determination of germ cell fates, the maintenance of germ cell identity, the migration of germ cells to the somatic gonadal primordia and the proliferation of germ cells during development invertebrates and invertebrates. Similarities in germline development in such diverse organisms as Drosophila melanogaster, Caenorhabditis elegans, Xenopus laevis and Mus musculus will be highlighted.
-
[
Curr Opin Microbiol,
2016]
Maintenance of genome integrity is essential. However, programmed DNA elimination removes specific DNA sequences from the genome during development. DNA elimination occurs in unicellular ciliates and diverse metazoa ranging from nematodes to vertebrates. Two distinct groups of nematodes use DNA elimination to silence germline-expressed genes in the soma (ascarids) or for sex determination (Strongyloides spp.). Data suggest that DNA elimination likely evolved independently in these nematodes. Recent studies indicate that differential CENP-A deposition within chromosomes defines which sequences are retained and lost during Ascaris DNA elimination. Additional studies are needed to determine the distribution, functions, and mechanisms of DNA elimination in nematodes.