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jun-D: a third member of the jun gene family
K Ryder1, A Lanahan, E Perez-Albuerne
1Howard Hughes Medical Institute Laboratory, Johns Hopkins University School of Medicine, Baltimore, MD 21205.
Abstract:
The protooncogene c-jun encodes a component of the transcription factor AP-1. Both murine c-jun and a related gene (jun-B) are rapidly activated in BALB/c3T3 cells by serum growth factors. We report here the cloning and analysis of a cDNA encoding a third member of the murine jun family, jun-D. The amino acid sequence encoded by jun-D has two extensive regions of homology with the other Jun proteins. One homology region includes the DNA-binding domain and sequences required for dimer formation and interaction with the Fos oncoprotein; the other includes the acidic sequence thought to be involved in gene activation. All three jun mRNAs are present in a variety of murine tissues and cell lines. In resting 3T3 cells, jun-D is expressed at a higher level compared to c-jun and jun-B, and its transcription is stimulated only slightly by serum growth factors. Thus, jun-D appears to be regulated differently than c-jun and jun-B.
Insights
Researchers identified a new gene, jun-D, in the Jun family of proteins. This jun-D gene is expressed differently than its counterparts, c-jun and jun-B, in mouse cells.
Area of Science:
- Molecular Biology
- Oncogenes
- Gene Regulation
Background:
- The protooncogene c-jun is a key component of the transcription factor AP-1.
- Murine c-jun and jun-B genes are rapidly activated by serum growth factors in BALB/c3T3 cells.
Purpose of the Study:
- To clone and analyze a cDNA encoding a third member of the murine jun family, designated jun-D.
- To investigate the structural homology and expression patterns of jun-D in comparison to c-jun and jun-B.
Main Methods:
- Cloning and analysis of jun-D cDNA.
- Amino acid sequence comparison between jun-D and other Jun proteins.
- Analysis of jun mRNA expression in various murine tissues and cell lines.
- Assessment of jun-D transcriptional regulation by serum growth factors.
Main Results:
- A cDNA encoding jun-D, a third murine jun family member, was successfully cloned and analyzed.
- The jun-D protein shares significant amino acid homology with c-jun and jun-B, including the DNA-binding and gene activation domains.
- jun-D mRNA is expressed in multiple murine tissues and cell lines.
- Unlike c-jun and jun-B, jun-D is highly expressed in resting 3T3 cells and shows only slight transcriptional stimulation by serum growth factors.
Conclusions:
- jun-D represents a distinct member of the murine jun gene family.
- jun-D exhibits differential regulation compared to c-jun and jun-B, particularly in response to growth factor stimulation.
- These findings suggest unique roles for jun-D in cellular processes.