Related Experiment Videos
La proteins from Xenopus laevis. cDNA cloning and developmental expression
D Scherly1, F Stutz, N Lin-Marq
1Département de Génétique et Microbiologie, Centre Médical Universitaire, Genève, Switzerland.
Journal of Molecular Biology
|May 20, 1993
Summary
This study reveals that Xenopus laevis has two related La proteins, crucial for RNA polymerase III transcription. Their levels decrease per cell during early development, despite constant overall amounts.
Area of Science:
- Developmental Biology
- Molecular Biology
- RNA Metabolism
Background:
- The La protein binds newly synthesized RNA polymerase III transcripts in mammalian nuclei.
- The La protein is a phosphorylated polypeptide of approximately 50 kDa.
Purpose of the Study:
- To investigate the presence and characteristics of La proteins in Xenopus laevis.
- To examine the expression levels of La mRNA and protein during early Xenopus development.
Main Methods:
- Analysis of Xenopus laevis mRNA sequences for La protein homologs.
- Quantification of La mRNA and protein levels in oocytes, eggs, and embryos.
Main Results:
- Xenopus laevis possesses mRNAs for two highly related La proteins, each from a single gene.
- Both La protein forms contain the RNP-80 motif, characteristic of RNA binding proteins.
- Steady-state levels of La mRNA and protein remain constant in oocytes, eggs, and embryos, indicating a decrease per cell during development.
Conclusions:
- Xenopus laevis has two La protein forms that are conserved RNA-binding proteins.
- La protein and mRNA levels do not increase at the mid-blastula transition, despite the onset of RNA polymerase III transcription.
- This suggests a regulatory mechanism for RNA polymerase III transcription during early embryogenesis.