The fusion of oocytes of the starfish Aphelasterias japonica III. Reconstruction of oocytes from cells and cell fragments (cytoplasts)

Vassetzky, S. G.; Sekirina, Galina G.; Veisman, Boris L.; Skoblina, M. N.; Bilinkis, Asya A.

doi:10.1016/0045-6039(84)90007-1

Cited by 9 publications

(5 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In order to increase the ratio of maturing cytoplasm to nucleus, a fusion technique was introduced, several basic studies of which have been made (8). Fig.…”

Section: Failure Of Gvbd In Mpf-injected Small Oocytesmentioning

confidence: 99%

Oocyte Competence to Maturation‐inducing Hormone. I. Breakdown of Germinal Vesicles of Small Oocytes in Starfish, *Asterina pectinifera**

1985

View full text Add to dashboard Cite

1-Methyladenine (1-MeAde) is the endogenous maturation-inducing substance (MIS) in starfish. However. small oocytes have no competence to 1-MeAde even at the concentration of 10V'M. Furthermore, when they were injected with cytoplasm of fully-grown (large) and maturing (1-MeAdetreated) oocytes, known to contain maturation-promoting factor (MPF), they did not undergo germinal vesicle breakdown (GVBD). On the other hand, germinal vesicles (GV) of the small oocytes underwent nuclear breakdown when the small oocytes were fused with the large maturing oocytes. Therefore it is concluded that the GV of the small oocytes are capable of undergoing nuclear breakdown in the presence of the sufficient MPF, but that the small oocytes can not amplify the injected MPF. Fused cells displayed particular shape changes during the course of nuclear breakdown of both the large and the small oocytes.In starfish it is well established that fully-grown oocytes (150-180pm in diameter, designated as large) are induced to resume maturation division by 1-methyladenine (1-MeAde), the endogenous maturation-inducing hormone secreted by follicle cells under the influence of gonad-stimulating substance (GSS) (1-5). Generally, 1-MeAde at concentrations around 10-8M can trigger germinal vesicle breakdown (GVBD). It has also been estabished that maturation-promoting factor (MPF) is generated in the large 1-MeAde-treated oocytes, and that the quantity increases during the process of GVBD (6). The quantity of MPF can be measured by transferring the cytoplasm of maturing oocytes into the large non-1-MeAdetreated oocytes, and by observing the occurrence of GVBD. Using this microinjection bioassay system, MPF can generally be detected about 10 min after the commencement of 1-MeAde treatment. The level increases gradually, reaching a plateau about 20 to 40 min after 1-MeAde treatment (20°C), after which the activity gradually decreases.However, in ma\\ oocytes (about three-quarters of the diameter of the large oocytes), GVBD does not occur even when they are treated with I-MeAde at a concentration of M. It was thought that a better understanding of the conditions necessary for meiosis would be reached through a comparison of the large (competent to 1-MeAde) and the small (non-competent to 1-MeAde) oocyte. Therefore we first tried to clarify why the small oocytes can not undergo GVBD, checking their ability (1) to generate MPF, and (2) to undergo * This paper is dedicated to our late Prof. H. Kanatani with deep respects and love.

show abstract

“…In order to increase the ratio of maturing cytoplasm to nucleus, a fusion technique was introduced, several basic studies of which have been made (8). Fig.…”

Section: Failure Of Gvbd In Mpf-injected Small Oocytesmentioning

confidence: 99%

Oocyte Competence to Maturation‐inducing Hormone. I. Breakdown of Germinal Vesicles of Small Oocytes in Starfish, *Asterina pectinifera**

1985

View full text Add to dashboard Cite

show abstract

“…In experiments on sea urchins (Bennet & Mazia, 1981) and starfish (Skoblina et al, 1982;Sekirina et al, 1983;Vassetzky et al, 1984Vassetzky et al, , 1993, differences in the colour and structure of the cytoplasm of the fusing cells have allowed its distribution during fusion to be followed. However, the process of cytoplasmic fusion has not been investigated in detail.…”

Section: Introductionmentioning

confidence: 98%

“…The consecutive stages of fusion of mouse oocytes (Soupart, 1980;Gulyas et al, 1984;Sekirina, 1985), sea urchin and starfish eggs (Skoblina et al, 1982;Sekirina et al, 1983;Vassetzky et al, , 1993, mouse blastomeres (Eglitis, 1980;Spindle, 1981;Sekirina, 1985), and fragments of oocytes, zygotes or blastomeres (Vassetzky et al, 1984(Vassetzky et al, ,1993Sekirina, 1985) have been recorded live on microphotographs. In experiments on sea urchins (Bennet & Mazia, 1981) and starfish (Skoblina et al, 1982;Sekirina et al, 1983;Vassetzky et al, 1984Vassetzky et al, , 1993, differences in the colour and structure of the cytoplasm of the fusing cells have allowed its distribution during fusion to be followed. However, the process of cytoplasmic fusion has not been investigated in detail.…”

Section: Introductionmentioning

confidence: 99%

The behaviour of mitochondria and cell integration during somatic hybridisation of sister blastomeres of the 2-cell mouse embryo

Sekirina

Bogoliubova

Antonova

et al. 1997

Zygote

View full text Add to dashboard Cite

The capacity of sister blastomeres of mouse embryos for induced fusion changed during the 2-cell stage. It was at low level (24%) at the early 2-cell stage, increased and reached 98.5% at the middle 2-cell stage and fell sharply to 31% at the late 2-cell stage. At the time corresponding to the G 2 /Mphase of the cell cycle the blastomeres fused in only 8% of cases. Vital staining of 2-cell embryos by rhodamine 123 showed that the mitochondria were dispersed throughout the cytoplasm with a ringlike (around the nucleus) or spot-like (over the metaphase plate) concentration in the centre of each blastomere. At the periphery of blastomeres the mitochondrial content was low. The behaviour of the mitochondria reflected the subsequent events of structural and functional integration of the sister blastomeres under induced fusion: a discernible boundary between partners during 30min after electrofusion or 1 h after fusion with polyethylene glycol; movement of the two 'rings' to the centre of the blastomere fusion products (BFP) to form one large bright 'spot' over the common metaphase plate; mitochondria outlining the shape of the spindle and connection between sister blastomeres until completion of the first mitosis of BFP. The data obtained suggest that fusion of the blastomeres does not lead to extensive changes in the hybrid cytoplasm and integration of nuclear material is taking place only at metaphase stage. Cytogenetic examination of BFP at the 2-cell stage confirmed reconstruction of the tetraploid embryos and found that sister blastomeres of such embryos could asynchronously enter the next cleavage division similarly to normal diploid 2-cell embryos.

show abstract

“…Some studies using the cell fusion technique in echinoderm development have been reported (1,2,16,17,22,23). In these studies, fused oocytes or eggs displayed only oocyte maturation (germinal vesicle breakdown) or several divisions.…”

Section: Cell Fusionmentioning

confidence: 99%

Reconstruction of Starfish Eggs by Electric Cell Fusion: A New Method of Detect the Cytoplasmic Determinant for Archenteron Formation

Kiyomoto¹,

Shirai²

1993

Dev Growth Differ

View full text Add to dashboard Cite

A method of detecting cytoplasm carrying the determinant for archenteron formation in starfish was established. Animal egg fragments (AEFs) which had been severed from the vegetal halves were fused electrically into pairs with fragments prepared from various regions of immature oocytes. It has been previously shown that the vegetal halves are exclusively endowed with the ability to form the archenteron; AEFs alone develop into so-called permanent blastulae. Eggs thus reconstructed were allowed to develop in order to assess the presence of the determinant in the added fragments. Only AEFs fused with fragments from near the vegetal pole of the oocytes formed the archenteron and developed into bipinnariae and juveniles.Comparison between the inner and outer (including cortex) cytoplasm of small vegetal fragment showed that the outer cytoplasm gave the reconstructed egg a greater ability to form an archenteron than the inner cytoplasm.

show abstract

The fusion of oocytes of the starfish Aphelasterias japonica III. Reconstruction of oocytes from cells and cell fragments (cytoplasts)

Cited by 9 publications

References 4 publications

Oocyte Competence to Maturation‐inducing Hormone. I. Breakdown of Germinal Vesicles of Small Oocytes in Starfish, *Asterina pectinifera**

Oocyte Competence to Maturation‐inducing Hormone. I. Breakdown of Germinal Vesicles of Small Oocytes in Starfish, *Asterina pectinifera**

The behaviour of mitochondria and cell integration during somatic hybridisation of sister blastomeres of the 2-cell mouse embryo

Reconstruction of Starfish Eggs by Electric Cell Fusion: A New Method of Detect the Cytoplasmic Determinant for Archenteron Formation

Contact Info

Product

Resources

About

The fusion of oocytes of the starfish Aphelasterias japonica III. Reconstruction of oocytes from cells and cell fragments (cytoplasts)

Cited by 9 publications

References 4 publications

Oocyte Competence to Maturation‐inducing Hormone. I. Breakdown of Germinal Vesicles of Small Oocytes in Starfish, Asterina pectinifera*

Oocyte Competence to Maturation‐inducing Hormone. I. Breakdown of Germinal Vesicles of Small Oocytes in Starfish, Asterina pectinifera*

The behaviour of mitochondria and cell integration during somatic hybridisation of sister blastomeres of the 2-cell mouse embryo

Reconstruction of Starfish Eggs by Electric Cell Fusion: A New Method of Detect the Cytoplasmic Determinant for Archenteron Formation

Contact Info

Product

Resources

About

Oocyte Competence to Maturation‐inducing Hormone. I. Breakdown of Germinal Vesicles of Small Oocytes in Starfish, *Asterina pectinifera**

Oocyte Competence to Maturation‐inducing Hormone. I. Breakdown of Germinal Vesicles of Small Oocytes in Starfish, *Asterina pectinifera**