Cells maintain control of their volume by the passage of KCI and water across their membranes, but the regulatory proteins are unknown. Expression in Xenopus oocytes of a novel protein, plan, activated a chloride conductance. We have cloned analogs of pIa. from rat heart and Xenopus ovary. pIa. was ldentified as an abundant soluble cytosolic protein (40 kd) that does not immunolocalize with the...

This issue of Mechanisms of Development addresses recent advances in Xenopus genomics and genetics, a topic whose time has undoubtedly come. Xenopus has long been a favourite species of the cell, molecular and (especially) developmental biologist. There are good reasons for this. Xenopus embryos are large and have reliable and accurate fate maps: they are therefore excellent for grafting and mi...

Electroporation is an efficient method of delivering DNA and other charged macromolecules into tissues at precise time points and in precise locations. For example, electroporation has been used with great success to study neural and retinal development in Xenopus, chicken and mouse (1-10). However, it is important to note that in all of these studies, investigators were not targeting soft tiss...

The scope of this commentary is to propose the incorporation of recent data, obtained from Xenopus eggs and embryos, into the models of cell cycle regulation by MPF, a universal M-phase Promoting Factor operating in most, if not all, mitotic cells, from yeast to human. These new data are: (1) the cycling activity of MPF in Xenopus eggs is temporally and functionally related to the cycling activ...

Epidermal fate in Xenopus ectoderm has been shown to be induced by a secreted growth factor, Bone Morphogenetic Protein 4 (BMP4). However, the molecular mechanism mediating this response is poorly understood. Here, we show that the expression of the homeobox gene, msx1, is an immediate early response to BMP4 in Xenopus embryos. The timing of expression and embryonic distribution of msx1 paralle...

Regeneration of boneless amputated forearms of adult newts was found to progress at a rate and to a degree comparable to amputated control limbs in which stump bones were not removed. In contrast, regeneration of boneless amputated Xenopus froglet forearms was significantly delayed and did not occur until two to three weeks following amputation. This is in comparison with the initiation of dist...

In Xenopus, a cytoplasmic agent known as MPF induces entry into mitosis. In fission yeast, genetic studies have shown that the cdc2 kinase regulates mitotic initiation. The 13 kd product of the suc1 gene interacts with the cdc2 kinase in yeast cells. We show that the yeast suc1 gene product (p13) is a potent inhibitor of MPF in cell-free extracts from Xenopus eggs. p13 appears to exert its anta...

Xenopus model. It provides wild-type, transgenic and mutant frogs to research labs at cost and can now also supply oocytes, embryos and frozen sperm. All of the GA animals are quality controlled to ensure that their offspring have the expected phenotype. In addition to these animal resources EXRC is gathering insitu hybridisation probes, relevant antibodies and expression clones from labs; agai...

To shed light on the organisation of the Xenopus laevis telencephalon, we have used two sets of developmental regulators: genes acting in early regional specification (x-Dll3, x-Nkx2.1, x-Emx1, x-Pax6, x-Eomes) or in cell determination (x-Lhx5 and x-Lhx7). After expression patterns analysis, separately or combined, on whole-mount brains and serial sections, we identify the Xenopus pallium and s...

Xenopus model. It provides wild-type, transgenic and mutant frogs to research labs at cost and can now also supply oocytes, embryos and frozen sperm. All of the GA animals are quality controlled to ensure that their offspring have the expected phenotype. In addition to these animal resources EXRC is gathering insitu hybridisation probes, relevant antibodies and expression clones from labs; agai...