Structural and mechanistic insights into the complexes formed by Wolbachia cytoplasmic incompatibility factors

2021 ◽  
Vol 118 (41) ◽  
pp. e2107699118
Author(s):  
Yunjie Xiao ◽  
Hongli Chen ◽  
Haofeng Wang ◽  
Mengwen Zhang ◽  
Xia Chen ◽  
...  
Keyword(s):  
Cytoplasmic Incompatibility ◽  
Germ Line ◽  
Large Fraction ◽  
Binding Mode ◽  
Transgenic Expression ◽  
Arthropod Species ◽  
Female Germ Line ◽  
And Function ◽  
Growth Analyses

Wolbachia bacteria, inherited through the female germ line, infect a large fraction of arthropod species. Many Wolbachia strains manipulate host reproduction, most commonly through cytoplasmic incompatibility (CI). CI, a conditional male sterility, results when Wolbachia-infected male insects mate with uninfected females; viability is restored if the female is similarly infected (called “rescue”). CI is used to help control mosquito-borne viruses such as dengue and Zika, but its mechanisms remain unknown. The coexpressed CI factors CifA and CifB form stable complexes in vitro, but the timing and function of this interaction in the insect are unresolved. CifA expression in the female germ line is sufficient for rescue. We report high-resolution structures of a CI-factor complex, CinA-CinB, which utilizes a unique binding mode between the CinA rescue factor and the CinB nuclease; the structures were validated by biochemical and yeast growth analyses. Importantly, transgenic expression in Drosophila of a nonbinding CinA mutant, designed based on the CinA-CinB structure, suggests CinA expressed in females must bind CinB imported by sperm in order to rescue embryonic viability. Binding between cognate factors is conserved in an enzymatically distinct CI system, CidA-CidB, suggesting universal features in Wolbachia CI induction and rescue.

scholarly journals Differences in size, structure and function of free and membrane-bound polyribosomes of rat liver. Evidence for a single class of membrane-bound polyribosomes

1977 ◽  
Vol 168 (1) ◽  
pp. 1-8 ◽  
Author(s):  
J C Ramsey ◽  
W J Steele
Keyword(s):  
Protein Synthesis ◽  
Rat Liver ◽  
Size Structure ◽  
Large Fraction ◽  
Liver Homogenate ◽  
Structure And Function ◽  
Structural And Functional Properties ◽  
Membrane Bound ◽  
And Function

Free loosely bound and tightly bound polyribosomes were separated from rat liver homogenate by salt extraction followed by differential centrifugation, and several of their structural and functional properties were compared to resolve the existence of loosely bound polyribosomes and verify the specificity of the separation. The free and loosely bound polyribosomes have similar sedimentation profiles and polyribosome contents, their subunit proteins have similar electrophoretic patterns and their products of protein synthesis in vitro show a close correspondence in size and amounts synthesized. In contrast, the tightly bound polyribosomes have different properties from those of the free and loosely bound polyribosomes; their average size is significantly smaller; their polyribosome content is higher; their 60 S-subunit proteins lack two components and contain four or more components not found elsewhere; their products of protein synthesis in vitro differ in size and amounts synthesized. These observations show that rat liver membranes entrap a large fraction of the free polyribosomes at low salt concentrations and that these polyribosomes are similar to those of the free-polyribosome fraction and are different from those of the tightly bound polyribosome fraction in size, structure and function.

scholarly journals Mitochondrial functionality in female reproduction

2017 ◽  
Vol 71 (1) ◽  
pp. 0-0
Author(s):  
Łukasz Gąsior ◽  
Regina Daszkiewicz ◽  
Mateusz Ogórek ◽  
Zbigniew Polański
Keyword(s):  
Mitochondrial Genome ◽  
Germ Cells ◽  
Germ Line ◽  
Whole Body ◽  
Female Reproduction ◽  
Normal Number ◽  
Female Germ Line ◽  
And Function ◽  
Role And Function

In most animal species female germ cells are the source of mitochondrial genome for the whole body of individuals. As a source of mitochondrial DNA for future generations the mitochondria in the female germ line undergo dynamic quantitative and qualitative changes. In addition to maintaining the intact template of mitochondrial genome from one generation to another, mitochondrial role in oocytes is much more complex and pleiotropic. The quality of mitochondria determines the ability of meiotic divisions, fertilization ability, and activation after fertilization or sustaining development of a new embryo. The presence of normal number of functional mitochondria is also crucial for proper implantation and pregnancy maintaining. This article addresses issues of mitochondrial role and function in mammalian oocyte and presents new approaches in studies of mitochondrial function in female germ cells.

Reconstitution in vitro of the entire cycle of the mouse female germ line

Nature ◽  
2016 ◽  
Vol 539 (7628) ◽  
pp. 299-303 ◽  
Author(s):  
Orie Hikabe ◽  
Nobuhiko Hamazaki ◽  
Go Nagamatsu ◽  
Yayoi Obata ◽  
Yuji Hirao ◽  
...  
Keyword(s):  
Germ Line ◽  
Female Germ Line

scholarly journals Protective effects of the cumulus-corona radiata complex during vitrification of horse oocytes

Reproduction ◽  
2009 ◽  
Vol 137 (3) ◽  
pp. 391-401 ◽  
Author(s):  
T Tharasanit ◽  
S Colleoni ◽  
C Galli ◽  
B Colenbrander ◽  
T A E Stout
Keyword(s):  
Connexin 43 ◽  
Germ Line ◽  
Lucifer Yellow ◽  
Cumulus Cells ◽  
Developmental Competence ◽  
Meiotic Spindle ◽  
Protective Effects ◽  
Gap Junction Communication ◽  
Female Germ Line

Vitrifying oocytes is a potentially valuable means of preserving the female germ line, but significantly compromises oocyte developmental competence. This study examined the hypothesis that the cumulus complex protects the oocyte during vitrification. Vitrified-warmed immature cumulus oocyte complexes (COCs) were labelled with a plasma membrane impermeant DNA marker (ethidium homodimer-1) to examine the percentage and location of dead cumulus cells, and to investigate the effect of the proportion of dead cells (+1,+2 or +3) on the success of in vitro maturation (IVM). Further, oocytes were labelled for connexin-43 or injected with Lucifer yellow dye to determine whether the integrity of the gap junctions between an oocyte and its cumulus was compromised by vitrification. Finally, the effect of denuding immature and mature oocytes on their ability to withstand vitrification was examined. Cryopreserving immature COCs increased the number of dead cumulus cells (13 vs 2.6% for controls; P<0.05). However, an increased proportion of dead cumulus cells did not affect post-warming maturation rates (∼30% MII) presumably because dead cells were located at the periphery of the cumulus mass and cumulus-oocyte gap junction communication was not disrupted. Moreover, cumulus removal prior to IVM or vitrification indicated that while the cumulus does protect immature oocytes during vitrification it does so by mechanisms other than support during maturation. Cumulus presence was also found to protect mature equine oocytes against vitrification-induced damage since cumulus-enclosed MII oocytes preserved their meiotic spindle quality better during vitrification than denuded oocytes (38.1 vs 3.1% normal spindles; P<0.05).

Effect of cumulus morphology and maturation stage on the cryopreservability of equine oocytes

Reproduction ◽  
2006 ◽  
Vol 132 (5) ◽  
pp. 759-769 ◽  
Author(s):  
T Tharasanit ◽  
S Colleoni ◽  
G Lazzari ◽  
B Colenbrander ◽  
C Galli ◽  
...  
Keyword(s):  
Intracytoplasmic Sperm Injection ◽  
Germ Line ◽  
Germinal Vesicle ◽  
Developmental Competence ◽  
Oocyte Cryopreservation ◽  
Meiotic Spindle ◽  
Maturation Stage ◽  
Blastocyst Formation ◽  
Female Germ Line

Oocyte cryopreservation is a potentially valuable way of preserving the female germ line. However, the developmental competence of cryopreserved oocytes is presently poor. This study investigated whether the morphology of the cumulus complex surrounding an immature equine oocyte and/or the oocyte’s stage of maturation affect its cryopreservability. Compact (Cp) and expanded (Ex) cumulus oocyte complexes (COCs) were vitrified either shortly after recovery (germinal vesicle stage, GV) or after maturation in vitro (IVM); cryoprotectant-treated and -untreated non-frozen oocytes served as controls. In Experiment I, oocytes matured in vitro and then vitrified, or vice versa, were examined for maturation stage and meiotic spindle quality. Cp and Ex COCs vitrified at the GV stage matured at similar rates during subsequent IVM (41 vs 46% MII), but meiotic spindle quality was better for Cp than Ex (63 vs 33% normal spindles). Vitrifying oocytes after IVM resulted in disappointing post-warming spindle quality (32 vs 28% normal for Cp vs Ex). In Experiment II, oocytes from Cp and Ex COCs vitrified at the GV or MII stages were fertilized by intracytoplasmic sperm injection (ICSI) and monitored for cleavage and blastocyst formation. Oocytes vitrified prior to IVM yielded higher cleavage rates (34 and 27% for Cp and Ex COCs) than those vitrified after IVM (16 and 4%). However, only one blastocyst was produced from a sperm-injected vitrified–warmed oocyte (0.4 vs 9.3% and 13% blastocysts for cryoprotectant-exposed and -untreated controls). It is concluded that, when vitrification is the chosen method of cryopreservation, Cp equine COCs at the GV stage offer the best chance of an MII oocyte with a normal spindle and the potential for fertilization; however, developmental competence is still reduced dramatically.

Identification and characterization of Drosophila female germ line transcriptional control elements

Development ◽  
1992 ◽  
Vol 114 (2) ◽  
pp. 481-491 ◽  
Author(s):  
L.H. Frank ◽  
H.K. Cheung ◽  
R.S. Cohen
Keyword(s):  
Copy Number ◽  
Transcriptional Control ◽  
Germ Line ◽  
Point Mutations ◽  
Target Site ◽  
Activator Proteins ◽  
Ideal System ◽  
Female Germ Line

The highly organized structure of the Drosophila ovary makes it an ideal system for studying mechanisms of differential gene expression. Here we report the identification of a 171 bp sequence from the 5' end of the hsp26 gene that functions as a female germ-line-specific transcriptional regulator when linked in two copies to a basal promoter. The regulator is active only in nondividing cells of the germ line, i.e., only in nurse cells and oocytes. It is not active in any examined tissue or cell type outside of the female germ line. Copper nuclease footprinting studies show that the germ line regulator contains two binding sites for each of two different ovarian nuclear factors. Point mutations in the DNA target sites of either nuclear factor abolish in vitro binding and in vivo transcriptional activity, indicating that each factor is a positive activator of nurse cell/oocyte transcription. The two factors may represent different classes of activator proteins, since an increase in the copy number of one factor's DNA target site cannot compensate for a decrease in the copy number of the other factor's target site.

scholarly journals Requirement of the Dynein-adaptor Spindly for mitotic and post-mitotic functions in Drosophila

2017 ◽  
Author(s):  
Giuliana D. Clemente ◽  
Matthew R. Hannaford ◽  
Jens Januschke ◽  
Eric R. Griffis ◽  
Hans-Arno J. Muller
Keyword(s):  
Germ Line ◽  
Mitotic Checkpoint ◽  
Checkpoint Protein ◽  
C Elegans ◽  
Protein Levels ◽  
Egg Morphology ◽  
Female Germ Line ◽  
And Function ◽  
Mitotic Checkpoint Protein ◽  
Dynactin Complex

AbstractSpindly is a mitotic checkpoint protein originally identified as a specific regulator of Dynein activity at the kinetochore. In metaphase, Spindly recruits the Dynein/Dynactin complex, promoting the establishment of stable kinetochore-microtubule interactions and progression into anaphase. While details of Spindly function in mitosis have been worked out in cultured human cells and in the C. elegans zygote, the function of Spindly within the context of an organism has not yet been addressed. Here we present loss- and gain-of-function studies of Spindly in Drosophila. We investigated the requirements of distinct protein domains for the localisation and function of Spindly. We find that knock-down of Spindly results in a range of mitotic defects in the female germ line and during cleavage divisions in embryogenesis. Overexpression of Spindly in the female germ line is embryonic lethal and results in altered egg morphology. To determine whether Spindly plays a role in post-mitotic cells we altered Spindly protein levels in migrating cells and found that ovarian border cell migration is sensitive to the levels of Spindly protein. Our study uncovers novel functions of the mitotic checkpoint protein Spindly in Drosophila.

Sign in / Sign up

Export Citation Format

Share Document