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Small B2 RNAs in mouse oocytes, embryos, and somatic tissues
1Department of Cell Biology and Anatomy, Cornell University Medical College, New York, New York 10021.
Developmental Biology
|December 1, 1988
Summary
Small B2 RNAs, repetitive genomic sequences, are found in mouse oocytes and embryos. Their levels change during development, suggesting a crucial role in these processes.
Area of Science:
- Molecular Biology
- Developmental Biology
- Genomics
Background:
- Small B2 RNAs are repetitive sequences found in the mouse genome.
- Previous studies identified heterogeneous polyadenylated B2-related RNA species.
Purpose of the Study:
- To analyze the presence and characteristics of small B2 RNAs in mouse oocytes, eggs, embryos, and somatic tissues.
- To investigate the changes in B2 RNA species during oocyte maturation and embryonic development.
Main Methods:
- Northern blot analysis using a single-stranded RNA probe to detect B2-related transcripts.
- Hybridization with oligo(dT) and RNase H cleavage to assess polyadenylation.
- Poly(U) sepharose binding to identify polyadenylated RNA species.
Main Results:
- Discrete nonadenylated B2 RNA species (100, 120, 155, and 180 nucleotides) were identified in addition to heterogeneous polyadenylated forms.
- The 155-nucleotide B2 RNA species increased during oocyte maturation, while the larger polyadenylated group declined.
- Small B2 RNAs are significantly more abundant in oocytes and eggs compared to brain tissue.
- B2 RNA levels per embryo increase during early development but decrease as a fraction of total RNA later on.
Conclusions:
- Polyadenylation, not run-on transcription, accounts for most of the heterogeneity in larger B2 RNA species.
- Deadenylation and cleavage of B2 RNAs occur during oocyte maturation.
- The dynamic expression pattern of small B2 RNAs suggests a significant role in mouse development.