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Molecular cloning and chromosomal localization of the human CITED2 gene encoding p35srj/Mrg1
M K Leung1, T Jones, C L Michels
1The Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, 02115, USA.
Abstract:
P35srj is a ubiquitously expressed nuclear protein that binds the transcriptional coactivators p300 and CREB-binding protein (CBP). It is an alternatively spliced isoform of Mrg1, a cytokine-inducible factor that has transformation activity. P35srj interferes with the recruitment of p300/CBP by the transcription factor HIF-1alpha, a process that is essential for the transcriptional response to hypoxia. Here we report the cloning of the human gene CITED2, which encodes p35srj and Mrg1. The CITED2 gene is composed of three exons and two introns. An unusually large (3 kb) CpG island covers both the promoter and the transcribed portions of the gene. The 5'-flanking region of the gene is active as a promoter in transient transfection assays and contains multiple STAT-binding sites, in keeping with its responsiveness to different cytokines. Fluorescence in situ hybridization, and identity to a known human sequence-tagged site (D6S2114), was used to map the CITED2 gene to chromosome 6q23.3.
Insights
Researchers cloned the human CITED2 gene, encoding the p35srj protein, which regulates hypoxia-induced gene expression by interfering with HIF-1alpha. This finding provides insight into cytokine-inducible gene regulation.
Area of Science:
- Molecular biology
- Genetics
- Cellular signaling
Background:
- P35srj is a nuclear protein binding p300 and CREB-binding protein (CBP).
- P35srj is an alternatively spliced isoform of Mrg1, a cytokine-inducible factor with transformation activity.
- P35srj inhibits HIF-1alpha recruitment of p300/CBP, crucial for hypoxia response.
Purpose of the Study:
- To clone the human gene encoding p35srj and Mrg1.
- To characterize the structure and regulatory elements of the CITED2 gene.
- To map the chromosomal location of the CITED2 gene.
Main Methods:
- Gene cloning and sequencing.
- Transient transfection assays to assess promoter activity.
- Fluorescence in situ hybridization (FISH) for gene mapping.
Main Results:
- The human CITED2 gene, encoding p35srj and Mrg1, was cloned.
- CITED2 comprises three exons and two introns, with a large CpG island.
- The 5'-flanking region contains STAT-binding sites, indicating cytokine responsiveness.
- CITED2 was mapped to chromosome 6q23.3 using FISH.
Conclusions:
- The CITED2 gene structure and regulatory elements support its role in cytokine-inducible gene expression.
- Understanding CITED2's function in hypoxia and cytokine signaling is crucial.
- The chromosomal localization of CITED2 provides a basis for further genetic studies.