Correlation between a DNA restriction fragment length polymorphism and C4A6 protein.

Area of Science:

• Immunogenetics
• Molecular Biology
• Human Genetics

Background:

• The fourth component of complement (C4) is encoded by C4A and C4B loci within the human major histocompatibility region (MHC) on chromosome 6.
• C4 genes exhibit extensive polymorphism with over 30 alleles, including null variants, making them useful for disease association studies.
• Previous studies suggest links between C4 phenotypes and autoimmune disorders such as systemic lupus erythematosus and type I diabetes.

Purpose of the Study:

• To investigate the correlation between C4 gene polymorphism and C4 protein phenotypes using molecular techniques.
• To establish a precise method for analyzing C4 polymorphism in genomic DNA.

Main Methods:

• Genomic DNA from individuals with known C4 protein types was analyzed using Southern blotting with a C4-specific probe.
• Restriction fragment length polymorphism (RFLP) analysis was performed using BglII restriction enzyme.

Main Results:

• Specific BglII restriction fragments of 10.7 kb and 3.8 kb were consistently identified in individuals expressing the C4A6 allele.
• These specific fragments were absent in individuals lacking the C4A6 allele, demonstrating a clear correlation.
• This molecular approach provides a precise basis for C4 polymorphism analysis.

Conclusions:

• Southern blotting with C4-specific probes and RFLP analysis effectively identifies C4 gene polymorphism.
• This technique offers a precise and valuable tool for analyzing C4 polymorphism, particularly in the context of autoimmune disease research.