GSBS Student Publications

Title

Poly(A) elongation during Xenopus oocyte maturation is required for translational recruitment and is mediated by a short sequence element

UMMS Affiliation

Program in Molecular Medicine; Worcester Foundation for Experimental Biology; Program in Molecular Medicine

Date

6-1-1989

Document Type

Article

Medical Subject Headings

Amino Acid Sequence; Animals; Base Sequence; Female; Gene Expression Regulation; Molecular Sequence Data; Oocytes; *Oogenesis; Poly A; *Protein Biosynthesis; *RNA Processing, Post-Transcriptional; RNA, Messenger; Recombinant Fusion Proteins; *Regulatory Sequences, Nucleic Acid; Xenopus laevis

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

Xenopus oocytes contain several mRNAs that are mobilized into polysomes only at the completion of meiosis (maturation) or at specific times following fertilization. To investigate the mechanisms that control translation during early development, we have focused on an mRNA, termed G10, that is recruited for translation during oocyte maturation. Coincident with its translation, the poly(A) tail of this message is elongated from approximately 90 to 200 adenylate residues. To identify the cis sequence that is required for this cytoplasmic adenylation and recruitment, we have synthesized wild-type and deletion mutant G10 mRNAs with SP6 polymerase. When injected into oocytes that subsequently were induced to mature with progesterone, wild-type G10 mRNA, but not mutant transcripts lacking a 50-base sequence in the 3'-untranslated region, was polyadenylated and recruited for translation. The 50-base sequence was sufficient to confer polyadenylation and translation when fused to globin mRNA, which does not normally undergo these processes during oocyte maturation. Further mutational analysis of this region revealed that a U-rich sequence 5' to the AAUAAA hexanucleotide nuclear polyadenylation signal, as well as the hexanucleotide itself, were both required for polyadenylation and translation. The 50-base cis element directs polyadenylation, but not translation per se, as a transcript that terminates with 3'-deoxyadenosine (cordycepin) is not recruited for translation. The available data suggest that the dynamic process of polyadenylation, and not the length of the poly(A) tail, is required for translational recruitment during oocyte maturation.

Rights and Permissions

Citation: Genes Dev. 1989 Jun;3(6):803-15.

Related Resources

Link to article in PubMed

Journal Title

Genes and development

PubMed ID

2568313