D. Ulgiati et Lj. Abraham, EXTENSIVE CONSERVATION OF UPSTREAM C4 PROMOTER SEQUENCES - A COMPARISON BETWEEN C4A AND C4B, Tissue antigens, 48(5), 1996, pp. 600-603
Basal levels of expression of complement C4 vary in individuals but it
is unknown whether this is due to gene copy number, protein clearance
rates or differences in expression. To investigate whether difference
s in the promoter region may influence transcription of the C4 genes,
we sequenced the promoter region of the C4B1 gene from the HLA-A1, B8,
C4AQ0, C4B1, DR3 haplotype and compared this with an equivalent C4A3
region. The promoter regions of the C4 genes were highly conserved, in
dicating that transcriptional differences are unlikely. An unusual fea
ture of the alignment was the higher level of polymorphism in the RP g
enes past the breakpoint of deletion/duplication in a region where the
highest conservation would be expected.