scholarly journals Receptor-mediated yolk uptake is required for oskar mRNA localization and cortical anchorage of germ plasm components in the Drosophila oocyte

PLoS Biology ◽  
2021 ◽  
Vol 19 (4) ◽  
pp. e3001183
Author(s):  
Tsubasa Tanaka ◽  
Naoki Tani ◽  
Akira Nakamura
Keyword(s):  
Germ Cell ◽  
Germ Plasm ◽  
Cell Formation ◽  
Mrna Localization ◽  
Posterior Pole ◽  
Actin Remodeling ◽  
Yolk Proteins ◽  
Anterior Dorsal ◽  
Cortical Anchorage ◽  
Germ Cell Formation

TheDrosophilagerm plasm is responsible for germ cell formation. Its assembly begins with localization ofoskarmRNA to the posterior pole of the oocyte. Theoskartranslation produces 2 isoforms with distinct functions: short Oskar recruits germ plasm components, whereas long Oskar remodels actin to anchor the components to the cortex. The mechanism by which long Oskar anchors them remains elusive. Here, we report that Yolkless, which facilitates uptake of nutrient yolk proteins into the oocyte, is a key cofactor for long Oskar. Loss of Yolkless or depletion of yolk proteins disrupts the microtubule alignment andoskarmRNA localization at the posterior pole of the oocyte, whereas microtubule-dependent localization ofbicoidmRNA to the anterior andgurkenmRNA to the anterior-dorsal corner remains intact. Furthermore, these mutant oocytes do not properly respond to long Oskar, causing defects in the actin remodeling and germ plasm anchoring. Thus, the yolk uptake is not merely the process for nutrient incorporation, but also crucial foroskarmRNA localization and cortical anchorage of germ plasm components in the oocyte.

Drosophila virilis oskar transgenes direct body patterning but not pole cell formation or maintenance of mRNA localization in D. melanogaster

Development ◽  
1994 ◽  
Vol 120 (7) ◽  
pp. 2027-2037 ◽  
Author(s):  
P.J. Webster ◽  
J. Suen ◽  
P.M. Macdonald
Keyword(s):  
Drosophila Melanogaster ◽  
Germ Cell ◽  
Cell Formation ◽  
Mrna Localization ◽  
Early Embryo ◽  
Posterior Pole ◽  
Early Embryogenesis ◽  
Drosophila Virilis ◽  
Pole Cell ◽  
Body Patterning

The Drosophila melanogaster gene oskar is required for both posterior body patterning and germline formation in the early embryo; precisely how oskar functions is unknown. The oskar transcript is localized to the posterior pole of the developing oocyte, and oskar mRNA and protein are maintained at the pole through early embryogenesis. The posterior maintenance of oskar mRNA is dependent upon the presence of oskar protein. We have cloned and characterized the Drosophila virilis oskar homologue, virosk, and examined its activity as a transgene in Drosophila melanogaster flies. We find that the cis-acting mRNA localization signals are conserved, although the virosk transcript also transiently accumulates at novel intermediate sites. The virosk protein, however, shows substantial differences from oskar: while virosk is able to rescue body patterning in a D. melanogaster oskar- background, it is impaired in both mRNA maintenance and pole cell formation. Furthermore, virosk induces a dominant maternal-effect lethality when introduced into a wild-type background, and interferes with the posterior maintenance of the endogenous oskar transcript in early embryogenesis. Our data suggest that virosk protein is unable to anchor at the posterior pole of the early embryo; this defect could account for all of the characteristics of virosk mentioned above. Our observations support a model in which oskar protein functions both by nucleating the factors necessary for the activation of the posterior body patterning determinant and the germ cell determinant, and by anchoring these factors to the posterior pole of the embryo. While the posterior body patterning determinant need not be correctly localized to provide body patterning activity, the germ cell determinant may need to be highly concentrated adjacent to the cortex in order to direct pole cell formation.

l(3)malignant brain tumor and Three Novel Genes Are Required for Drosophila Germ-Cell Formation

Genetics ◽  
2003 ◽  
Vol 165 (4) ◽  
pp. 1889-1900 ◽  
Author(s):  
Christopher B Yohn ◽  
Leslie Pusateri ◽  
Vitor Barbosa ◽  
Ruth Lehmann
Keyword(s):  
Brain Tumor ◽  
Germ Cell ◽  
Germ Plasm ◽  
Nuclear Division ◽  
Cell Formation ◽  
Nuclear Migration ◽  
Early Embryo ◽  
Malignant Brain Tumor ◽  
Mitotic Synchrony ◽  
Germ Cell Formation

Abstract To identify genes involved in the process of germ-cell formation in Drosophila, a maternal-effect screen using the FLP/FRT-ovoD method was performed on chromosome 3R. In addition to expected mutations in the germ-cell determinant oskar and in other genes known to be involved in the process, several novel mutations caused defects in germ-cell formation. Mutations in any of three genes [l(3)malignant brain tumor, shackleton, and out of sync] affect the synchronous mitotic divisions and nuclear migration of the early embryo. The defects in nuclear migration or mitotic synchrony result in a reduction in germ-cell formation. Mutations in another gene identified in this screen, bebra, do not cause mitotic defects, but appear to act upstream of the localization of oskar. Analysis of our mutants demonstrates that two unique and independent processes must occur to form germ cells—germ-plasm formation and nuclear division/migration.

The fat facets gene is required for Drosophila eye and embryo development

Development ◽  
1992 ◽  
Vol 116 (4) ◽  
pp. 985-1000 ◽  
Author(s):  
J.A. Fischer-Vize ◽  
G.M. Rubin ◽  
R. Lehmann
Keyword(s):  
Amino Acids ◽  
Germ Cell ◽  
Protein Function ◽  
Cell Formation ◽  
Posterior Pole ◽  
Hybrid Protein ◽  
Drosophila Eye ◽  
Fat Facets ◽  
Pole Plasm ◽  
Germ Cell Formation

In a screen for mutations affecting Drosophila eye development, we have identified a gene called fat facets (faf) which is required for cell interactions that prevent particular cells in the developing eye from becoming photoreceptors. Analysis of eyes mosaic for faf+ and faf- cells shows that faf is required in cells near to, but outside, normal developing photoreceptors and also outside of the ectopic photoreceptors in mutant facets. faf is also essential during oogenesis, and we show that a faf-lacZ hybrid protein is localized via the first 392 amino acids of faf to the posterior pole of oocytes. Posterior localization of faf-lacZ depends on oskar. oskar encodes a key organizer of the pole plasm, a specialized cytoplasm at the posterior pole of embryos. The pole plasm is required for germ cell formation and contains the determinant of posterior polarity, encoded by nanos. Although other pole plasm components are required for localization of nanos RNA or for nanos protein function, faf is not. We have cloned the faf gene, and have shown that it encodes two similar large (approximately 300 × 10(3) M(r)) proteins that are unique with respect to other known proteins.

scholarly journals Human germ cell formation in xenotransplants of induced pluripotent stem cells carrying X chromosome aneuploidies

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Antonia A. Dominguez ◽  
H. Rosaria Chiang ◽  
Meena Sukhwani ◽  
Kyle E. Orwig ◽  
Renee A. Reijo Pera
Keyword(s):  
Stem Cells ◽  
Germ Cell ◽  
Induced Pluripotent Stem Cells ◽  
X Chromosome ◽  
Pluripotent Stem Cells ◽  
Cell Formation ◽  
Induced Pluripotent ◽  
Germ Cell Formation

OVARIAN TERATOMAS AND GENETICS OF GERM-CELL FORMATION

The Lancet ◽  
1977 ◽  
Vol 309 (8007) ◽  
pp. 362-363 ◽  
Author(s):  
P.A. Riley ◽  
P.M. Sutton
Keyword(s):  
Germ Cell ◽  
Cell Formation ◽  
Germ Cell Formation ◽  
Ovarian Teratomas

scholarly journals Germ Cell-less Promotes Centrosome Segregation to Induce Germ Cell Formation

Cell Reports ◽  
2017 ◽  
Vol 18 (4) ◽  
pp. 831-839 ◽  
Author(s):  
Dorothy A. Lerit ◽  
Conrad W. Shebelut ◽  
Kristen J. Lawlor ◽  
Nasser M. Rusan ◽  
Elizabeth R. Gavis ◽  
...  
Keyword(s):  
Germ Cell ◽  
Cell Formation ◽  
Germ Cell Formation

Oskar anchoring restricts pole plasm formation to the posterior of the Drosophila oocyte

Development ◽  
2002 ◽  
Vol 129 (15) ◽  
pp. 3705-3714 ◽  
Author(s):  
Nathalie F. Vanzo ◽  
Anne Ephrussi
Keyword(s):  
Drosophila Melanogaster ◽  
Translational Control ◽  
Cell Formation ◽  
Positional Information ◽  
Mrna Localization ◽  
Posterior Pole ◽  
Tight Coupling ◽  
Anteroposterior Patterning ◽  
Pole Cell ◽  
Pole Plasm

Localization of the maternal determinant Oskar at the posterior pole of Drosophila melanogaster oocyte provides the positional information for pole plasm formation. Spatial control of Oskar expression is achieved through the tight coupling of mRNA localization to translational control, such that only posterior-localized oskar mRNA is translated, producing the two Oskar isoforms Long Osk and Short Osk. We present evidence that this coupling is not sufficient to restrict Oskar to the posterior pole of the oocyte. We show that Long Osk anchors both oskar mRNA and Short Osk, the isoform active in pole plasm assembly, at the posterior pole. In the absence of anchoring by Long Osk, Short Osk disperses into the bulk cytoplasm during late oogenesis, impairing pole cell formation in the embryo. In addition, the pool of untethered Short Osk causes anteroposterior patterning defects, owing to the dispersion of pole plasm and its abdomen-inducing activity throughout the oocyte. We show that the N-terminal extension of Long Osk is necessary but not sufficient for posterior anchoring, arguing for multiple docking elements in Oskar. This study reveals cortical anchoring of the posterior determinant Oskar as a crucial step in pole plasm assembly and restriction, required for proper development of Drosophila melanogaster.

207 ESTABILSHMENT OF CYNOMOLGUS MONKEY EMBRYONIC STEM CELL LINES AND CONFIRMATION OF THE POSSIBILITY FOR GERMINAL COMPETENCY

2006 ◽  
Vol 18 (2) ◽  
pp. 211
Author(s):  
T. Teramura ◽  
N. Kawata ◽  
N. Fujinami ◽  
M. Takenoshita ◽  
N. Sagawa ◽  
...  
Keyword(s):  
Germ Cell ◽  
Cell Lines ◽  
Cynomolgus Monkey ◽  
Primordial Germ Cell ◽  
Cell Formation ◽  
Embryonic Stem ◽  
Alp Activity ◽  
Weak Expression ◽  
Germ Cell Formation

Embryonic stem cells (ESCs) of nonhuman primate are important tools for human gametogenesis research. Generally, ESCs, embryos, and fetuses of nonhuman primates are similar to these of human. Recently, germ cell formation of mouse ESCs in vitro has been reported. In this study, we established new cynomolgus monkey ES (cyES) lines and determined germinal competency by assessing expression of mRNA markers. CyES lines were established using blastocysts produced by intracytoplasmic sperm injection (ICSI). For inducing super-ovulation, females were treated with 25 IU/kg pregnant mare serum gonadotropin (PMSG) once a day for 9 days, followed by 400 IU/kg hCG. Oocytes were collected 40 h after injection of hCG. After sperm injection, embryos were cultured in mCMRL medium to the blastocyst stage. For ES line establishment, inner cell masses (ICMs) were isolated by immunosurgery. ESC colonies emerged at about 10 days after ICM plating; three cyES cell lines were successfully obtained (3/11; 27.3%). We characterized these lines by immunocytochemistry for Oct-3/4, SSEA-3, and SSEA-4, which are diagnostic markers for primate ESCs, and by assay for alkaline phosphatase (ALP) activity. All cell lines expressed Oct-3/4, SSEA-4 and ALP activity. The previously reported SSEA-3 weak expression in cyES cells was not observed. These lines differentiated spontaneously when they were replaced in non-adherent culture (embryoid body: EB) or injected into SCID mice subcutaneously. To assess germ cell competency in vitro, we analyzed for the presence of vasa mRNA which shows a restricted expression pattern to germ cell formation, and DMC1 and SYCP1 which show specific existence on synaptonema complex in meiosis. Detection of these germ cell markers was performed by RT-PCR with total cDNA from ESCs and EBs. Nanog mRNA was detected only in ESCs. Oct-4 was detected in gonadal tissue of both sexes, ESCs, and EBs. Vasa was expressed in testis, but not in ESCs or somatic cells. Interestingly, we recognized weak expression of Vasa in Day 12-16 EBs. DMC1 and SYCP1 as meiosis markers were not detected. Because Oct-4 and Vasa mRNA are transcribed simultaneously, similar to that in the early part of gametogenesis such as the latter period of primordial germ cell (PGC) migration, PGC formation in cynomolgus EBs could occurr as in some cases of mouse or human EBs previously reported. Although detailed properties such as the functions of these Vasa-positive cells have not been confirmed, these results demonstrate that cyES cells obtained in the current study might contribute to putative germ cells in vitro by differentiating to EBs. This study was supported by a Grant-in-Aid for the 21st Century COE Program of the Japan Mext and by a grant for the Wakayama Prefecture Collaboration of Regional Entities for the Advancement of Technology Excellence of the JST.

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