Contextualizing Autophagy during Gametogenesis and Preimplantation Embryonic Development

Mammals face environmental stressors throughout their lifespan, which may jeopardize cellular homeostasis. Hence, these organisms have acquired mechanisms to cope with stressors by sensing, repairing the damage, and reallocating resources to increase the odds of long-term survival. Autophagy is a pro-survival lysosome-mediated cytoplasm degradation pathway for organelle and macromolecule recycling. Furthermore, autophagy efflux increases, and this pathway becomes idiosyncratic depending upon developmental and environmental contexts. Mammalian germ cells and preimplantation embryos are attractive models for dissecting autophagy due to their metastable phenotypes during differentiation and exposure to varying environmental cues. The aim of this review is to explore autophagy during mammalian gametogenesis, fertilization and preimplantation embryonic development by contemplating its physiological role during development, under key stressors, and within the scope of assisted reproduction technologies.

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Comparison of the symbiotic and competition phenotypes of Sinorhizobium meliloti PHB synthesis and degradation pathway mutants

Canadian Journal of Microbiology ◽

10.1139/w05-042 ◽

2005 ◽

Vol 51 (7) ◽

pp. 599-604 ◽

Cited By ~ 20

Author(s):

P Aneja ◽

A Zachertowska ◽

T C Charles

Keyword(s):

Sinorhizobium Meliloti ◽

Degradation Pathway ◽

Nodule Occupancy ◽

Wild Type ◽

Term Survival ◽

Mutant Strains ◽

Key Factor ◽

Carbon Excess ◽

Synthesis And Degradation

The competitive abilities of Sinorhizobium meliloti mutant strains containing lesions in the PHB synthesis (phbC) and degradation (bdhA) pathways were compared. While the bdhA mutant showed no noticeable symbiotic defects on alfalfa host plants when inoculated alone, in mixed inoculation experiments it was found to be less competitive than the wild type for nodule occupancy. Long-term survival of the bdhA mutant on a carbon-limiting medium was not affected. However, when subjected to competition with the wild-type strain in periodic subculturing through alternating carbon-limiting and carbon-excess conditions, the bdhA mutant performed poorly. A more severe defect in competition for growth and nodule occupancy was observed with a mutant unable to synthesize PHB (phbC). These results indicate that the ability to efficiently deposit cellular PHB stores is a key factor influencing competitive survival under conditions of fluctuating nutrient carbon availability, whereas the ability to use these stores is less important.Key words: Sinorhizobium meliloti, PHB metabolism, competition.

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The TALE Homeodomain Protein Pbx2 Is Not Essential for Development and Long-Term Survival

Molecular and Cellular Biology ◽

10.1128/mcb.24.12.5324-5331.2004 ◽

2004 ◽

Vol 24 (12) ◽

pp. 5324-5331 ◽

Cited By ~ 51

Author(s):

Licia Selleri ◽

Jorge DiMartino ◽

Jan van Deursen ◽

Andrea Brendolan ◽

Mrinmoy Sanyal ◽

...

Keyword(s):

Embryonic Development ◽

Late Gestation ◽

Homeodomain Protein ◽

Mammalian Development ◽

Term Survival ◽

Long Term Survival ◽

Embryonic Tissues ◽

Adult Mice ◽

Tale Homeodomain

ABSTRACT Pbx2 is one of four mammalian genes that encode closely related TALE homeodomain proteins, which serve as DNA binding partners for a subset of Hox transcription factors. The expression and contributions of Pbx2 to mammalian development remain undefined, in contrast to the essential roles recently established for family members Pbx1 and Pbx3. Here we report that Pbx2 is widely expressed during embryonic development, particularly in neural and epithelial tissues during late gestation. Despite wide Pbx2 expression, mice homozygous mutant for Pbx2 are born at the expected Mendelian frequencies and exhibit no detectable abnormalities in development and organogenesis or reduction of long-term survival. The lack of an apparent phenotype in Pbx2− /− mice likely reflects functional redundancy, since the Pbx2 protein is present at considerably lower levels than comparable isoforms of Pbx1 and/or Pbx3 in embryonic tissues. In postnatal bone marrow and thymus, however, Pbx2 is the predominant high-molecular-weight (MW)-isoform Pbx protein detectable by immunoblotting. Nevertheless, the absence of Pbx2 has no measurable effect on steady-state hematopoiesis or immune function in adult mice, suggesting possible compensation by low-MW-isoform Pbx proteins present in these tissues. We conclude that the roles of Pbx2 in murine embryonic development, organogenesis, hematopoiesis, immune responses, and long-term survival are not essential.

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Genetic Analysis of the Roles of daf28 and age-1 in Regulating Caenorhabditis elegans Dauer Formation

Genetics ◽

10.1093/genetics/143.3.1193 ◽

1996 ◽

Vol 143 (3) ◽

pp. 1193-1205 ◽

Cited By ~ 5

Author(s):

Elizabeth A Malone ◽

Takao Inoue ◽

James H Thomas

Keyword(s):

Life Span ◽

Environmental Cues ◽

Apparent Effect ◽

Term Survival ◽

Dauer Larva ◽

Extend Life Span ◽

Unique Aspect ◽

Dauer Formation ◽

Harsh Conditions

Abstract Based on environmental cues, the nervous system of Caenorhabditis ekgans regulates formation of the dauer larva, an alternative larval form specialized for long-term survival under harsh conditions. Mutations that cause constitutive or defective dauer formation (Daf-c or Daf-d) have been identified and the genes ordered in a branched pathway. Most Daf-c mutations also affect recovery from the dauer stage. The semidominant mutation daf-28(sa191) is Daf-c but has no apparent effect on dauer recovery. We use this unique aspect of daf28(sal91) to characterize the effects of several Daf-d and synthetic Daf-c mutations on dauer recovery. We present double mutant analysis that indicates that daf-28(saI91) acts at a novel point downstream in the genetic pathway for dauer formation. We also show that daf-28(sa191) causes a modest increase (12-13%) in life span. The phenotypes and genetic interactions of daf-28(sa191) are most similar to those of daf-2 and daf-23 mutations, which also cause a dramatic increase in life span. We present mapping and complementation data that suggest that daf-23 is the same gene as age-I, identified previously by mutations that extend life span. We find that age-l alleles are also Daf-c at 27°.

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Long-Term Maintenance and Meiotic Entry of Early Germ Cells in Murine Testicular Organoids Functionalized by 3D Printed Scaffolds and Air-Medium Interface Cultivation

Frontiers in Physiology ◽

10.3389/fphys.2021.757565 ◽

2021 ◽

Vol 12 ◽

Author(s):

Guillaume Richer ◽

Robin M. Hobbs ◽

Katherine L. Loveland ◽

Ellen Goossens ◽

Yoni Baert

Keyword(s):

Germ Cells ◽

Mouse Strains ◽

Term Survival ◽

Tissue Degeneration ◽

Testicular Cells ◽

Medium Interface ◽

3D Printed ◽

Cell Functionality ◽

Air Medium

Short-term germ cell survival and central tissue degeneration limit organoid cultures. Here, testicular organoids (TOs) were generated from two different mouse strains in 3D printed one-layer scaffolds (1LS) at the air-medium interface displaying tubule-like structures and Leydig cell functionality supporting long-term survival and differentiation of germ cells to the meiotic phase. Chimeric TOs, consisting of a mixture of primary testicular cells and EGFP+ germline stem (GS) cells, were cultured in two-layer scaffolds (2LSs) for better entrapment. They showed an improved spheroidal morphology consisting of one intact tubule-like structure and surrounding interstitium, representing the functional unit of a testis. However, GS cells did not survive long-term culture. Consequently, further optimization of the culture medium is required to enhance the maintenance and differentiation of germ cells. The opportunities TOs offer to manipulate somatic and germ cells are essential for the study of male infertility and the search for potential therapies.

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Effects of Gangliosides on Spermatozoa, Oocytes, and Preimplantation Embryos

International Journal of Molecular Sciences ◽

10.3390/ijms21010106 ◽

2019 ◽

Vol 21 (1) ◽

pp. 106 ◽

Cited By ~ 3

Author(s):

Bo Hyun Kim ◽

Won Seok Ju ◽

Ji-Su Kim ◽

Sun-Uk Kim ◽

Soon Ju Park ◽

...

Keyword(s):

Embryonic Development ◽

Oocyte Maturation ◽

Germ Cells ◽

Preimplantation Embryos ◽

Ovarian Maturation ◽

Functional Roles ◽

Oocyte Cytoplasm ◽

In Vitro Oocyte Maturation ◽

Ganglioside Gt1b

Gangliosides are sialic acid-containing glycosphingolipids, which are the most abundant family of glycolipids in eukaryotes. Gangliosides have been suggested to be important lipid molecules required for the control of cellular procedures, such as cell differentiation, proliferation, and signaling. GD1a is expressed in interstitial cells during ovarian maturation in mice and exogenous GD1a is important to oocyte maturation, monospermic fertilization, and embryonic development. In this context, GM1 is known to influence signaling pathways in cells and is important in sperm–oocyte interactions and sperm maturation processes, such as capacitation. GM3 is expressed in the vertebrate oocyte cytoplasm, and exogenously added GM3 induces apoptosis and DNA injury during in vitro oocyte maturation and embryogenesis. As a consequence of this, ganglioside GT1b and GM1 decrease DNA fragmentation and act as H2O2 inhibitors on germ cells and preimplantation embryos. This review describes the functional roles of gangliosides in spermatozoa, oocytes, and early embryonic development.

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Caspases and apoptosis

Essays in Biochemistry ◽

10.1042/bse0380009 ◽

2002 ◽

Vol 38 ◽

pp. 9-19 ◽

Cited By ~ 121

Author(s):

Guy S Salvesen

Keyword(s):

Cysteine Proteases ◽

Signalling Pathways ◽

Term Survival ◽

Mature Adult ◽

Intracellular Signalling Pathways ◽

Adult Cell ◽

Caspase Family ◽

Cell Fragments ◽

Pro Inflammatory Cytokines

The ability of metazoan cells to undergo programmed cell death is vital to both the precise development and long-term survival of the mature adult. Cell deaths that result from engagement of this programme end in apoptosis, the ordered dismantling of the cell that results in its 'silent' demise, in which packaged cell fragments are removed by phagocytosis. This co-ordinated demise is mediated by members of a family of cysteine proteases known as caspases, whose activation follows characteristic apoptotic stimuli, and whose substrates include many proteins, the limited cleavage of which causes the characteristic morphology of apoptosis. In vertebrates, a subset of caspases has evolved to participate in the activation of pro-inflammatory cytokines, and thus members of the caspase family participate in one of two very distinct intracellular signalling pathways.

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