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cDNA cloning, tissue expression, and chromosomal assignment of a mouse gene, encoding a 127 kDa UV-damaged DNA
1Genome Research Group, National Institute of Radiological Sciences, Chiba, Japan.
Abstract:
A subset of xeroderma pigmentosum (XP) group E cells lack a factor of the UV-damaged DNA binding activity. Both 127 kDa and 48 kDa proteins have been reported to be responsible for the binding activity. A cDNA for the 127 kDa UV-damaged DNA-binding protein (p127-Ddb1) was isolated from a mouse fetal brain full length-enriched cDNA library, and an open reading frame of 1140 amino acids was identified. Reverse transcription-coupled polymerase chain reaction (RT-PCR) showed that mouse Ddb1 messenger is ubiquitously expressed in adult tissues as well as in embryo's. The gene was mapped to near the public locus D19Mit22 region of mouse chromosome 19.
Insights
Researchers identified the mouse UV-damaged DNA-binding protein (Ddb1) gene, crucial for DNA repair in xeroderma pigmentosum. This gene is widely expressed and located on mouse chromosome 19, aiding in understanding DNA repair mechanisms.
Area of Science:
- Molecular Biology
- Genetics
- DNA Repair
Background:
- Xeroderma pigmentosum (XP) group E cells exhibit deficient UV-damaged DNA binding activity.
- Both 127 kDa and 48 kDa proteins are implicated in this DNA binding activity.
Purpose of the Study:
- To isolate and characterize the cDNA for the 127 kDa UV-damaged DNA-binding protein (p127-Ddb1).
- To investigate the expression pattern and chromosomal location of the mouse Ddb1 gene.
Main Methods:
- cDNA library screening using mouse fetal brain.
- Identification of open reading frame (ORF) and amino acid sequence.
- Reverse transcription-coupled polymerase chain reaction (RT-PCR) for gene expression analysis.
- Gene mapping using mouse genetic markers.
Main Results:
- A cDNA encoding the 127 kDa UV-damaged DNA-binding protein (p127-Ddb1) was successfully isolated.
- The identified mouse Ddb1 gene has an open reading frame of 1140 amino acids.
- Mouse Ddb1 messenger RNA is ubiquitously expressed in adult tissues and embryos.
- The Ddb1 gene was mapped to mouse chromosome 19, near the D19Mit22 locus.
Conclusions:
- The mouse Ddb1 gene encodes a key protein involved in UV-damaged DNA binding.
- Ubiquitous expression suggests a fundamental role in DNA repair across various tissues and developmental stages.
- The chromosomal localization provides a genetic marker for further studies on Ddb1 and related pathways.