Regulated expression of the retinoblastoma gene product by fibroblast growth factor but not by activin during mesoderm induction in Xenopus

1996 ◽  
Vol 206 (5) ◽  
pp. 333-336
Author(s):  
J. Greenland ◽  
L L. Gillespie
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Gene Product ◽  
Mesoderm Induction ◽  
Fibroblast Growth ◽  
Retinoblastoma Gene ◽  
Regulated Expression ◽  
Retinoblastoma Gene Product

Nuclear translocation of fibroblast growth factor during Xenopus mesoderm induction

Development ◽  
1991 ◽  
Vol 113 (2) ◽  
pp. 487-493 ◽  
Author(s):  
R.A. Shiurba ◽  
N. Jing ◽  
T. Sakakura ◽  
S.F. Godsave
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Nuclear Translocation ◽  
Cell Interaction ◽  
Mesoderm Induction ◽  
Nuclear Staining ◽  
Fibroblast Growth ◽  
Polypeptide Growth Factors ◽  
Vegetal Pole

Mesoderm induction, the earliest inductive cell-cell interaction in vertebrate embryogenesis, is thought to be mediated by polypeptide growth factors including fibroblast growth factor (FGF). Here we present an immunocytochemical analysis of FGF during mesoderm induction in Xenopus laevis. Antibodies to both basic and acidic FGF were immunoreactive with oocytes and early embryos. Immunostaining was predominantly intracellular and was concentrated in the marginal zone and vegetal pole throughout cleavage and blastula stages. In addition, basic FGF (bFGF) antibodies showed intense nuclear staining in these regions, at and following the mid-blastula transition, when embryonic transcription begins. Acidic FGF (aFGF) also appeared in some nuclei at these stages. Taken together the evidence suggests that FGF is prepositioned in mesoderm-forming regions and is actively involved in mesoderm induction in vivo.

scholarly journals The retinoblastoma gene product regulates Sp1-mediated transcription.

1992 ◽  
Vol 12 (6) ◽  
pp. 2455-2463 ◽  
Author(s):  
S J Kim ◽  
U S Onwuta ◽  
Y I Lee ◽  
R Li ◽  
M R Botchan ◽  
...  
Keyword(s):  
Growth Factor ◽  
Gene Product ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Control Element ◽  
Retinoblastoma Gene ◽  
Insulinlike Growth Factor ◽  
Factor Ii ◽  
Retinoblastoma Gene Product

We have demonstrated that the retinoblastoma gene product (Rb) can positively regulate transcription from the fourth promoter of the insulinlike growth factor II gene. Two copies of a motif (the retinoblastoma control element) similar to that found in the human c-fos, transforming growth factor beta 1, and c-myc promoters are responsible for conferring Rb regulation to the fourth promoter of the insulinlike growth factor II gene. We have shown that the transcription factor Sp1 can bind to and stimulate transcription from the retinoblastoma control element motif. Moreover, by using a GAL4-Sp1 fusion protein, we have directly demonstrated that Rb positively regulates Sp1 transcriptional activity in vivo. These results indicate that Rb can function as a positive regulator of transcription and that Sp1 is one potential target, either directly or indirectly, for transcriptional regulation by Rb.

scholarly journals AP-1/Jun Is Required for EarlyXenopusDevelopment and Mediates Mesoderm Induction by Fibroblast Growth Factor but Not by Activin

1996 ◽  
Vol 271 (17) ◽  
pp. 9942-9946 ◽  
Author(s):  
Zigang Dong ◽  
Ren-He Xu ◽  
Jaebong Kim ◽  
Shu-Ning Zhan ◽  
Wei-Ya Ma ◽  
...  
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Mesoderm Induction ◽  
Fibroblast Growth

Basic fibroblast growth factor induces notochord formation and the expression of As-T, a Brachyury homolog, during ascidian embryogenesis

Development ◽  
1996 ◽  
Vol 122 (7) ◽  
pp. 2023-2031 ◽  
Author(s):  
Y. Nakatani ◽  
H. Yasuo ◽  
N. Satoh ◽  
H. Nishida
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Basic Fibroblast Growth Factor ◽  
Mesoderm Induction ◽  
Fibroblast Growth ◽  
Halocynthia Roretzi ◽  
Cell Stage ◽  
Inductive Interaction ◽  
Notochord Cells

The tadpole larva of an ascidian develops 40 notochord cells in the center of its tail. Most of the notochord cells originate from the A-line precursors, among which inductive interactions are required for the subsequent differentiation of notochord. The presumptive-endoderm blastomeres or presumptive-notochord blastomeres themselves are inducers of notochord formation. Notochord induction takes place during the 32-cell stage. In amphibia, mesoderm induction is thought to be mediated by several growth factors, for example, activins and basic fibroblast growth factor (bFGF). In the ascidian, Halocynthia roretzi, treatment with bFGF of presumptive-notochord blastomeres that had been isolated at the early 32-cell stage promoted the formation of notochord at a low concentration of bFGF (0.02 ng/ml), while activin failed to induce notochord differentiation. The effect of bFGF reached a maximum at the end of the 32-cell stage and rapidly faded at the beginning of the subsequent cleavage, the time for full induction of notochord being at least 20 minutes. The expression of As-T, a previously isolated ascidian homolog of the mouse Brachyury (T) gene, starts at the 64-cell stage and is detectable exclusively in the presumptive-notochord blastomeres. The present study showed that presumptive-notochord blastomeres, isolated at the early 32-cell stage, neither differentiated into notochord nor expressed the As-T gene. However, when the presumptive-notochord blastomeres were coisolated or recombined with inducer blastomeres, transcripts of As-T were detected. When presumptive-notochord blastomeres were treated with bFGF, the expression of the As-T gene was also detected. These results suggest that inductive interaction is required for the expression of the As-T gene and that the expression of the As-T gene is closely correlated with the determined state of the notochord-precursor cells.

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