Mr 25 000 protein, a substrate for protein serine/threonine kinases, is identified as a part of Xenopus laevis vitellogenin B1.
A phosphorylated protein with a molecular mass of 25 000 (pp25) previously purified from the cytosolic fraction of Xenopus laevis oocytes is an effective phosphate acceptor for casein kinases and protein kinase C. In this study, based on the partial amino acid sequence of pp25, a cDNA was isolated that encodes a new yolk precursor protein, Xenopus vitellogenin B1, which contained the sequence encoding pp25. Both mRNA and protein of vitellogenin B1 were expressed in all of the female organs examined. In agreement with a previous report, the amount of vitellogenin B1 protein in the liver increased after stimulation with estrogen. These results suggest that pp25 is a cytosolic non-crystallized yolk protein nutrient source, but it might also play a role in rapid development.
Yoshitome
Satoshi
S
Division of Pathological Biochemistry, Department of Biomedical Sciences, School of Life Sciences, Faculty of Medicine, Tottori University, 86 Nishicho, Yonago 683-8503, Japan.
Nakamura
Hiroyasu
H
Nakajo
Nobushige
N
Okamoto
Kengo
K
Sugimoto
Isamu
I
Kohara
Hiromi
H
Kitayama
Kaori
K
Igarashi
Kazuaki
K
Ito
Susumu
S
Sagata
Noriyuki
N
Hashimoto
Eikichi
E
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D018076:DNA, Complementary / Q000235:genetics; D004967:Estrogens / Q000378:metabolism; D020224:Expressed Sequence Tags; D005260:Female; D020869:Gene Expression Profiling; D008969:Molecular Sequence Data; D009865:Oocytes / Q000737:chemistry*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011506:Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014819:Vitellogenins / Q000737:chemistry* / Q000235:genetics; D014982:Xenopus laevis / Q000235:genetics*
D018076:DNA, Complementary; D004967:Estrogens; D011506:Proteins; D014819:Vitellogenins; D017346:Protein Serine-Threonine Kinases