Xtr, a plural tudor domain-containing protein, is involved in the translational regulation of maternal mRNA during oocyte maturation in Xenopus laevis.
Xtr in the fertilized eggs of Xenopus has been demonstrated to be a member of a messenger ribonucleoprotein (mRNP) complex that plays a crucial role in karyokinesis during cleavage. Since the Xtr is also present both in oocytes and spermatocytes and its amount increases immediately after spematogenic cells enter into the meiotic phase, this protein was also predicted to act during meiotic progression. Taking advantage of Xenopus oocytes' large size to microinject anti-Xtr antibody into them for inhibition of Xtr function, we examined the role of Xtr in meiotic progression of oocytes. Microinjection of anti-Xtr antibody into immature oocytes followed by reinitiation of oocyte maturation did not affect germinal vesicle break down and the oscillation of Cdc2/cyclin B activity during meiotic progression but caused abnormal spindle formation and chromosomal alignment at meiotic metaphase I and II. Immunoprecipitation of Xtr showed the association of Xtr with FRGY2 and mRNAs such as RCC1 and XL-INCENP mRNAs, which are involved in the progression of karyokinesis. When anti-Xtr antibody was injected into oocytes, translation of XL-INCENP mRNA, which is known to be repressed in immature oocytes and induced after reinitiation of oocyte maturation, was inhibited even if the oocytes were treated with progesterone. A similar translational regulation was observed in oocytes injected with a reporter mRNA, which was composed of an enhanced green fluorescent protein open reading frame followed by the 3' untranslational region (3'UTR) of XL-INCENP mRNA. These results indicate that Xtr regulates the translation of XL-INCENP mRNA through its 3'UTR during meiotic progression of oocyte.
Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto, 860-8555, Japan.
Hiroki
H
Ohgami
Masateru
M
Hiyoshi
Md Golam
MG
Mostafa
Hideo
H
Kubo
Shin-Ichi
S
Abe
Kazufumi
K
Takamune
D000818:Animals; D000906:Antibodies / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D048750:Cell Nucleus Division; D005260:Female; D018507:Gene Expression Regulation, Developmental; D008540:Meiosis; D008845:Microinjections; D009865:Oocytes / Q000166:cytology / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D011374:Progesterone / Q000494:pharmacology; D014176:Protein Biosynthesis; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis
D000906:Antibodies; D018797:Cell Cycle Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; C471810:TDRD6 protein, Xenopus; D014157:Transcription Factors; D029867:Xenopus Proteins; C075593:YBX2 protein, Xenopus; D011374:Progesterone; D011494:Protein Kinases; C070577:CDK1 protein, Xenopus