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Messenger RNA expressed in mouse teratocarcinoma stem cells and down-regulated by a tumor-promoting phorbol ester
J Akagi1, H Nomiyama, C Setoyama
1Department of Biochemistry, Kumamoto University Medical School, Japan.
Abstract:
Cloning and sequence analysis of a DNA complementary to the mRNA expressed in undifferentiated mouse F9 teratocarcinoma stem cells but disappearing rapidly after treatment with a tumor-promoting phorbol ester revealed it to be a 1.9 kilobase pairs-long cDNA encoding a protein of 323 amino acid residues. Computer-assisted analyses of the deduced amino acid sequence indicated that this protein contains a typical hydrophobic signal peptide consisting of 33 amino acid residues and six putative membrane-spanning segments. The deduced amino acid sequence, as a whole, bears no significant sequence homology to any previously described protein.
Insights
Researchers identified a novel protein in mouse teratocarcinoma stem cells that disappears upon tumor promoter treatment. This protein has a signal peptide and membrane-spanning regions, with no known sequence similarity to other proteins.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Mouse F9 teratocarcinoma stem cells are a model for early embryonic development.
- Tumor-promoting phorbol esters can induce differentiation and alter gene expression in these cells.
Purpose of the Study:
- To clone and analyze the DNA complementary to a specific mRNA.
- To characterize a protein that is rapidly downregulated by phorbol ester treatment in F9 cells.
Main Methods:
- Cloning of complementary DNA (cDNA).
- Sequence analysis of the cDNA and deduced amino acid sequence.
- Computer-assisted analysis for protein structural motifs.
Main Results:
- A 1.9 kilobase pair cDNA was isolated, encoding a 323 amino acid protein.
- The protein possesses a hydrophobic signal peptide (33 amino acids) and six predicted membrane-spanning segments.
- No significant sequence homology was found with known proteins.
Conclusions:
- A novel protein, potentially involved in F9 cell differentiation or response to tumor promoters, has been identified.
- The protein's predicted structure suggests it is membrane-associated.