Human p53 cellular tumor antigen: cDNA sequence and expression in COS cells

Area of Science:

• Molecular Biology
• Oncology
• Immunology

Background:

• The p53 tumor antigen is a critical factor in cellular regulation and cancer development.
• Understanding the molecular characteristics of human p53 is essential for cancer research and therapeutic development.

Purpose of the Study:

• To isolate and characterize the complementary DNA (cDNA) clone for human p53 tumor antigen.
• To compare the human p53 sequence with its mouse counterpart and assess its functional expression.

Main Methods:

• Isolation of a 2.5-kb cDNA clone encoding the full coding region of human p53.
• Nucleotide sequence comparison between human and mouse p53.
• Expression of the human p53 cDNA in SV40-based vectors.
• Analysis of the produced polypeptide using monoclonal antibodies against p53.

Main Results:

• A 2.5-kb cDNA clone for human p53 was successfully isolated, containing the complete coding sequence.
• Human p53 comprises 393 residues, differing from mouse p53 by six additional codons in exon 4.
• DNA sequence homology between human and mouse p53 coding regions is 81%, with uneven conservation.
• Expressed human p53 cDNA produced a 55 kd polypeptide, precipitable by anti-p53 monoclonal antibodies.

Conclusions:

• The isolated human p53 cDNA clone is functional and directs the synthesis of a recognizable p53 polypeptide.
• Sequence comparison reveals significant homology but also species-specific differences in p53 structure.
• This research provides a valuable tool for further investigation into p53's role in tumorigenesis and potential therapeutic strategies.