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Published on: December 14, 2015
Sequence and developmental expression of mRNA coding for a gap junction protein in Xenopus
R L Gimlich1, N M Kumar, N B Gilula
1Department of Molecular Biology, Research Institute of Scripps Clinic, La Jolla, California 92037.
The Journal of Cell Biology
|September 1, 1988
Summary
Researchers isolated and sequenced embryonic gap junction protein cDNAs in Xenopus laevis. This protein is crucial during early development, with its transcript found in specific embryonic tissues and adult organs like lungs and kidneys.
Area of Science:
- Developmental Biology
- Molecular Biology
- Genetics
Background:
- Gap junction proteins are essential for intercellular communication.
- Understanding embryonic gap junction proteins provides insights into developmental processes.
- Xenopus laevis serves as a valuable model organism for studying vertebrate development.
Purpose of the Study:
- To isolate and characterize complementary DNAs (cDNAs) encoding an embryonic gap junction protein in Xenopus laevis.
- To determine the expression pattern of this embryonic gap junction protein during development and in adult tissues.
- To analyze the sequence and structural similarities of the Xenopus embryonic gap junction protein with its mammalian counterparts.
Main Methods:
- Cloning and sequencing of complementary DNAs (cDNAs).
- RNA hybridization to analyze transcript abundance and distribution.
- In vitro translation to confirm protein product size.
- Bioinformatic analysis for sequence similarity comparisons.
Main Results:
- Isolation and sequencing of cDNAs for a Xenopus laevis embryonic gap junction protein.
- The corresponding 1.5 kb RNA transcript is first detected during gastrulation and accumulates through neurulation, with highest abundance in ventroposterior endoderm and liver rudiment by the tailbud stage.
- Adult expression is observed in lungs, alimentary tract, and kidneys, but not in brain, heart, muscles, spleen, or ovary.
- The gene is present in low copy numbers in the frog genome.
- In vitro translation yields a 30-kD protein with sequence similarity to mammalian gap junction proteins, particularly in transmembrane and extracellular domains, but with divergence in intracellular domains.
Conclusions:
- A novel embryonic gap junction protein in Xenopus laevis has been identified and characterized.
- The expression pattern suggests a role in specific developmental processes and adult organ function.
- Structural comparisons reveal conserved and divergent regions compared to mammalian gap junction proteins, offering insights into functional evolution.
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