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Molecular characterization of the interferon-induced 15-kDa protein. Molecular cloning and nucleotide and amino acid
Abstract:
We have isolated a cDNA clone for an interferon-induced 15-kDa protein. The cDNA clone was prepared from mRNA isolated from interferon-beta-treated human Daudi cells. The clone of 635 base pairs contains an open reading frame coding for a protein of 145 amino acids, and suggests for the mRNA a 75-base pair 5' untranslated and a 125-base pair 3' untranslated region. Approximately 85% of the amino acid sequence of the 15-kDa protein has been independently obtained from 2 nmol of material using microsequencing technology on the N terminus of the intact protein and on tryptic and chymotryptic peptides. The amino acid sequence of the isolated protein is identical to the amino acid sequence deduced from the cDNA. Northern blot analysis confirmed that the mRNA for the 15-kDa protein is undetectable in untreated cells, but is greatly induced following interferon treatment.
Insights
Researchers isolated a cDNA clone for a 15-kDa interferon-induced protein. This protein
Area of Science:
- Molecular Biology
- Immunology
- Cell Biology
Background:
- Interferons are crucial signaling proteins in the immune system.
- Interferon-beta is known to induce various cellular responses.
- Understanding interferon-induced proteins is key to deciphering immune regulation.
Purpose of the Study:
- To isolate and characterize a cDNA clone for a 15-kDa interferon-induced protein.
- To confirm the protein's sequence and its induction by interferon-beta.
- To investigate the molecular basis of interferon-mediated cellular responses.
Main Methods:
- cDNA library construction from interferon-beta-treated Daudi cells.
- DNA sequencing to determine the open reading frame and untranslated regions.
- Protein microsequencing (N-terminal, tryptic, chymotryptic peptides).
- Northern blot analysis to assess mRNA expression levels.
Main Results:
- A 635-base pair cDNA clone was isolated, encoding a 145-amino acid protein.
- The deduced amino acid sequence matched the microsequenced protein sequence (85% coverage).
- mRNA for the 15-kDa protein was undetectable in untreated cells but highly induced by interferon-beta.
Conclusions:
- The study successfully isolated and characterized the cDNA for a 15-kDa interferon-induced protein.
- The findings confirm the protein's identity and its transcriptional regulation by interferon-beta.
- This work contributes to understanding the molecular mechanisms of interferon signaling.