pEg7, a new Xenopus protein required for mitotic chromosome condensation in egg extracts.
We have isolated a cDNA, Eg7, corresponding to a Xenopus maternal mRNA, which is polyadenylated in mature oocytes and deadenylated in early embryos. This maternal mRNA encodes a protein, pEg7, whose expression is strongly increased during oocyte maturation. The tissue and cell expression pattern of pEg7 indicates that this protein is only readily detected in cultured cells and germ cells. Immunolocalization in Xenopus cultured cells indicates that pEg7 concentrates onto chromosomes during mitosis. A similar localization of pEg7 is observed when sperm chromatin is allowed to form mitotic chromosomes in cytostatic factor-arrested egg extracts. Incubating these extracts with antibodies directed against two distinct parts of pEg7 provokes a strong inhibition of the condensation and resolution of mitotic chromosomes. Biochemical experiments show that pEg7 associates with Xenopus chromosome-associated polypeptides C and E, two components of the 13S condensin.
Cubizolles
F
F
Biologie et Génétique du Développement, CNRS UPR 41, Université de Rennes I, Campus de Beaulieu, 35042 Rennes cedex, France.
Legagneux
V
V
Le Guellec
R
R
Chartrain
I
I
Uzbekov
R
R
Ford
C
C
Le Guellec
K
K
D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D002478:Cells, Cultured; D002875:Chromosomes / Q000502:physiology*; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D004527:Egg Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D008297:Male; D008938:Mitosis; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes; D009865:Oocytes / Q000166:cytology / Q000502:physiology*; D016366:Open Reading Frames; D009928:Organ Specificity; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014020:Tissue Extracts / Q000378:metabolism; D014981:Xenopus; D029867:Xenopus Proteins
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C116601:Eg7 protein, Xenopus; D004527:Egg Proteins; D046912:Multiprotein Complexes; D011994:Recombinant Proteins; D014020:Tissue Extracts; D029867:Xenopus Proteins; C108312:condensin complexes; D000251:Adenosine Triphosphatases