A physical map of the human complement component C6, C7, and C9 genes

Area of Science:

• Genetics
• Immunology
• Molecular Biology

Background:

• The human complement system comprises proteins crucial for innate immunity.
• Genes for complement components C6, C7, and C9 are known to be located on chromosome 5.
• Understanding the physical arrangement of these genes is important for studying their coordinated expression and potential regulatory mechanisms.

Purpose of the Study:

• To physically map and determine the linkage between the human complement component 6 (C6) and complement component 7 (C7) genes.
• To investigate the orientation and relative arrangement of the C6 and C7 genes.
• To assess the physical linkage of the complement component 9 (C9) gene with C6 and C7.

Main Methods:

• Pulsed field gel electrophoresis (PFGE) was employed to separate large DNA fragments.
• Rare-cutting restriction enzymes were used to digest genomic DNA.
• Southern blot hybridization with cDNA probes specific to C6 and C7 was performed to detect gene linkage.

Main Results:

• Physical linkage was established between the C6 and C7 genes.
• Both C6 and C7 genes were found within a 500 kilobase (kb) NotI restriction fragment.
• Analysis of common 3' fragments indicated a tail-to-tail, reverse transcriptional orientation for C6 and C7.
• No physical linkage between C9 and C6 or C7 was detected within a range of 50 kilobases (kb) to 2.5 megabases (Mb).

Conclusions:

• The C6 and C7 genes are physically linked on chromosome 5 and arranged in a tail-to-tail orientation.
• The C9 gene is not physically linked to C6 and C7 within the analyzed genomic region.
• These findings contribute to the genetic mapping of the human complement system and provide insights into gene organization.