Characterization, mapping, and expression of the human ceruloplasmin gene

Area of Science:

• Biochemistry
• Genetics
• Molecular Biology

Background:

• Ceruloplasmin (CP) is a vital copper-binding protein found in vertebrate plasma.
• CP is encoded by a gene resulting from intragenic triplication, comprising three homologous domains.

Purpose of the Study:

• To identify and characterize cDNA clones encoding human ceruloplasmin (CP).
• To analyze the sequence homology within the CP gene and compare it to other human proteins.
• To determine the chromosomal location of the CP gene and investigate potential related sequences.

Main Methods:

• Oligonucleotide probes were used to identify human CP cDNA clones.
• Sequence analysis was performed to compare nucleotide sequences of CP domains and homologous proteins.
• Somatic-cell-hybrid analysis and in situ hybridization were employed for gene mapping.
• DNA polymorphism detection using Pst I endonuclease digestion and CP cDNA.
• In situ histohybridization was used to detect CP mRNA in various human tissues.

Main Results:

• Two distinct cDNA clones, CP-1 and CP-2, were identified, representing 81% of the CP coding sequence.
• Internal domain homology within the CP coding sequence ranged from 50.1% to 56%.
• The CP-2 cDNA sequence showed 48% overall identity to human clotting factor VIII.
• The CP gene was mapped to human chromosome 3 (3q25), with evidence of additional CP-like DNA sequences.
• A DNA polymorphism was detected using Pst I, and CP mRNA was found in liver, macrophages, and lymphocytes.

Conclusions:

• The study successfully identified and characterized human CP cDNA clones, providing insights into its genetic structure.
• The findings confirm internal homology within the CP gene and its chromosomal localization.
• Evidence suggests the presence of additional CP-like sequences in the human genome, warranting further investigation.