The Immortal Germline

The immortal germline
Copyright
Contributors
Preface
The vertebrate Balbiani body, germ plasm, and oocyte polarity
Introduction
Inductive and inherited germ cell specification
Inheritance of germ plasm
The Balbiani body: A conserved oocyte organelle
Early oocyte development and the Balbiani body in mice
Early oocyte development in zebrafish
The Balbiani body in zebrafish and frogs
The role of mitochondria in the Balbiani body
Bucky ball: An essential Balbiani body protein
Macf1 and Balbiani body disassembly
Secondary pathway mRNA localization
Animal pole mRNA localization
Concluding remarks
Acknowledgments
References
Genetic basis for primordial germ cells specification in mouse and human: Conserved and divergent roles of P ...
Introduction
Early developmental divergence in mammalian embryos
Modeling peri-implantation development and PGC specification
PGC-like cell specification from pluripotent cells in vitro
Developmental models based on self-organizing properties of pluripotent cells
Gene regulatory networks for mouse and human PGC specification
The genetic basis for mouse PGC specification
Distinct network for human PGC development
Differential roles of SOX factors in mouse and human PGC specification
SOX17 is crucial for human, but not mouse PGC fate
SOX2 is a key pluripotency TF required for mouse PGC development, but absent from human germline
PRDM family genes in mouse and human PGC specification
BLIMP1 is a conserved PGC regulator in mouse and human
PRDM14 is critical for mouse PGC fate with unclear functions in human PGCs
Perspective
Acknowledgments
References
Germ cell reprogramming
Introduction
Mouse germ cell reprogramming
Specification and development of mouse primordial germ cells
In vitro reconstitution of mouse PGC specification from pluripotent stem cells
Epigenome reprogramming during mouse PGC specification in vitro
Transcriptional regulation
Dynamics of chromatin remodeling
Dynamics of DNA methylation
Epigenome reprogramming in migrating mPGCs and gonadal germ cells before sex differentiation
Continuous DNA demethylation
Histone modification
Epigenome programming in sexually differentiating germ cells in embryonic gonads
In vitro proliferation of migrating mPGCs on plane culture
Induction of the female germ cell pathway and initiation of meiosis in vitro
Derivation of the male germ cell pathway in vitro
Epigenome programming in mouse oogenesis
DNA methylation and chromatin remodeling
Histone replacement
Three-dimensional organization of the genome
Epigenome programming during mouse spermatogenesis
Human germ cell reprogramming
Specification and development of human PGCs
Development of human gonadal germ cells
Epigenome reprogramming of human gonadal germ cells
Heterogeneous transcriptome dynamics in human germ cell development
In vitro reconstitution of human PGCs from pluripotent stem cells
Epigenome reprogramming during in vitro reconstitution of human PGCs and their differentiation into oogonia
Conclusion and perspectives
Acknowledgment
Funding
References
From worm to germ: Germ cell development and regeneration in planarians
Introduction
Planarian biology: Some background about the ``other´´ worm
Germ cell-intrinsic regulation
Reproductive system regeneration
Asexuals ``do it´´ too
An unbiased screen for germ cell regulators
Extrinsic regulation via local cues
The niche is back: The somatic gonad and germ cell regeneration
Extrinsic regulation via systemic cues
Sex on the brain: A role for neuropeptides
A welcome reception: Roles for small-molecule receptors in the soma
A blurred line between neoblasts and germ cells
References
Heterogeneity of primordial germ cells
Introduction
Heterogeneous phenotypes of primordial germ cells
Primordial germ cell specification and heterogeneity
PGC specification by preformation
PGC specification by induction
Primordial germ cell migration and heterogeneity
Proliferation of primordial germ cells and heterogeneity
Primordial germ cell survival and heterogeneity
Differentiation of PGCs and heterogeneity
Determinants of heterogeneity
Genetic determinants
Acquired genetic changes
Pre-existing genetic changes
Epigenetic determinants
Non-genetic determinants
Extrinsic sources of heterogeneity: Environment, niche, and timing
Buffers of heterogeneity
Selection and heterogeneity
Defining selection in the developing germline
How does PGC fitness relate to fitness of gametes or individuals?
Conclusion
References
Germline stem cell homeostasis
Introduction
Specifying and maintaining germline stem cells
The niche signaling that maintains germline stem cells
Cell adhesion maintains the niche architecture
The mechanisms that restrict the effective range of the niche signaling
Cell intrinsic factors required for GSC self-renewal
Somatic control of germline differentiation
Asymmetric stem cell division
The mechanisms of asymmetric stem cell division
Asymmetric segregation of cellular components
Transit-amplifying divisions to reduce the burden on stem cells
Dedifferentiation maintains GSC populations beyond the lifespan of individual cells
Dedifferentiation creates GSCs to replace lost GSCs
The mechanism of dedifferentiation
Are dedifferentiated GSCs equal to native GSCs?
Cell death in GSC homeostasis
SG death induced by somatic CC apoptosis shifts tissue homeostasis during starvation
SG death as a mechanism to protect germline genome integrity
Differential sensitivity to cell death among distinct cell populations
The disruption of germline homeostasis during aging
Maintaining the germline over successive generations
Conclusion
Acknowledgments
References
Heterogeneous, dynamic, and stochastic nature of mammalian spermatogenic stem cells
Introduction
Key questions about SSCs
The stem-cell system in Drosophila spermatogenesis
Overview of mouse spermatogenesis in adult testes
Spermatogenic cell types
Seminiferous tubules
The seminiferous epithelial cycle and spermatogenic wave
Interstitial compartment
Advantages and available techniques in the study of SSCs
Advantageous anatomy of seminiferous tubules
Transplantation
In vitro SSC culture in 2D
Ex vivo organ culture in 3D
Intravital live imaging
In vivo pulse-labeling fate analysis
Single-cell ``omics´´ study
In vitro gametogenesis from pluripotent cells
Statistics, mathematics, and theory
Identity and dynamics of SSCs
The ``As model´´
Heterogeneous and hierarchical transcriptional states within Aundiff population
Extension of the As model
Clonal fate variability: Population asymmetry and neutral competition
Syncytial fragmentation: Interchange between topologically different states
Context dependent interchange between different transcriptional states
Dynamic heterogeneity: A paradigm of stem-cell homeostasis?
Future questions about the SSC identity
Microenvironmental regulation of SSCs
Scattered distribution of Aundiff in the basal compartment
Biased distribution toward interstitium and blood vessels
Motion of spermatogonia
Spatiotemporal distribution of extracellular signaling factors in an open (facultative) niche microenvironment
Heterogeneous susceptibility to extracellular signals
Density regulation through the mechanism of mitogen competition
Next questions
Conclusion
Acknowledgments
References
Sperm success and immunity
Introduction
Sperm success and the male immune system
Expensive ejaculates and trade-offs with immunity
Antagonistic pleiotropy between sperm success and immune capacity
Vertebrate male sperm auto-immunity
Effects of infections in males, including STIs, on sperm success
Sperm success and the female immune system
Female reproductive tract immunity effects on sperm success
Immunity and sperm storage in females
The role of female immunity in post-copulatory sexual selection: Immune-mediated cryptic female choice
Conclusions
Acknowledgments
References
A symbiont´s guide to the germline
Background: Symbiont transmission modes maintain symbiotic associations
Soma-to-soma strategies of vertical symbiont transmission
Vertical transmission through the germline part 1: Migration from the soma to oocytes/embryos
Transmission without tissue types: Sponge symbiont transmission
Extracellular storage of vertically transmitted intracellular symbionts
Intracellular symbiont transmission from the soma to the germline involves cell-to-cell transfer
Vertical transmission through the germline part 2: Migration from the soma to germ stem cells (GSCs)
Vertical transmission through the germline part 3: Continuous germ cell association throughout development
Segregation with host cell division: The first form of vertical transmission
Symbiont segregation with the primordial germline
Continuous germ line association is not the norm among strictly vertically transmitted symbionts
Parallels between symbiont transmission and the origin of the germline
Conclusions
References