Thesaurin a, the major protein of Xenopus laevis previtellogenic oocytes, present in the 42 S particles, is homologous to elongation factor EF-1 alpha.
We have purified in SDS X.laevis thesaurin a (Mr 50,000) which is part of the 42 S storage particles. Its N-terminal amino acid is blocked and several peptides obtained by V8 protease treatment were purified and sequenced. As expected from one of the functional roles of the 42 S particles (tRNA binding, protection against deacylation and exchange with the ribosome), the amino acid sequence of thesaurin a was found to be closely related to that of the elongation factor EF-1 alpha. We suggest that all three proteins involved in 5 S RNA and tRNA storage in previtellogenic oocytes, TFIIIA, thesaurin a and thesaurin b, have a dual function: storage and a role in transcription or in protein synthesis.
Viel
A
A
Centre de Génétique Moléculaire, Associé à l'Université de Paris VI, Gif-sur-Yvette, France.
Djé
M K
MK
Mazabraud
A
A
Denis
H
H
le Maire
M
M
D000595:Amino Acid Sequence; D000818:Animals; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism*; D009866:Oogenesis; D020648:Peptide Elongation Factor 1; D010445:Peptide Elongation Factors / Q000378:metabolism; D012261:Ribonucleoproteins / Q000032:analysis* / Q000378:metabolism; D014982:Xenopus laevis / Q000502:physiology*
D020648:Peptide Elongation Factor 1; D010445:Peptide Elongation Factors; D012261:Ribonucleoproteins