Figure 1
From: Real-time PCR quantification of human complement C4A and C4B genes
Modular variations of human complement C4 and RP-C4-CYP21-TNX (RCCX) modules in the MHC class III region. Each C4 (Complement C4) gene may code either the C4A or the C4B protein, and may consist of 21 kb (long, containing the HERV-K endogenous retrovirus) or 14.6 kb (short). RP: Ser/Thr protein kinase, CYP21: Steroid 21-hydroxylase, TNX: Extracellular matrix protein tenascin-X.