Dataset Information


Identification and characterization of a sphere organelle protein.

ABSTRACT: Sphere organelles are nuclear structures in amphibian oocytes that are easily visible by light microscopy. These structures are up to 10 microns in diameter and have been described morphologically for decades, yet their function remains obscure. The present study defines a protein component of the sphere organelle, named SPH-1, which is recognized by a mAb raised against purified Xenopus laevis oocyte nucleoplasm. SPH-1 is an 80-kD protein which is localized specifically to spheres and is undetectable elsewhere on lampbrush chromosomes or in nucleoli. We show using confocal microscopy that SPH-1 is localized to the cortex of sphere organelles. Furthermore, we have isolated a cDNA that can encode SPH-1. When epitope-tagged forms of SPH-1 are expressed in X. laevis oocytes the protein specifically localizes to spheres, demonstrating that the cloned cDNA encodes the sphere antigen. Comparison of the predicted amino acid sequence with sequence databases shows SPH-1 is related to p80-coilin, a protein associated with coiled bodies; coiled bodies are nuclear structures found in plant and animal cells. The sphere-specific mAb stains X. laevis tissue culture cells in a punctate nuclear pattern, showing that spheres or sphere antigens are present in somatic cells as well as germ cells and suggesting a general and essential function for spheres in all nuclei.

PROVIDER: S-EPMC2119590 | BioStudies | 1993-01-01T00:00:00Z

REPOSITORIES: biostudies

Similar Datasets

1994-01-01 | S-EPMC301135 | BioStudies
| S-EPMC4581859 | BioStudies
2022-06-01 | GSE162845 | GEO
1998-01-01 | S-EPMC147939 | BioStudies
| S-EPMC6676608 | BioStudies
1997-01-01 | S-EPMC147103 | BioStudies
| S-EPMC84422 | BioStudies
2019-01-01 | S-EPMC6650401 | BioStudies
| S-EPMC3434318 | BioStudies
2018-07-10 | GSE98776 | GEO