DNA
methylation
analysis
of
chromosome
21
gene
promoters at single base pair and single allele resolution
Yingying Zhang, Christian Rohde, Sascha Tierling, Tomasz P. Jurkowski, Christoph
Bock, Diana Santacruz, Sergey Ragozin, Richard Reinhardt, Marco Groth, Jörn
Walter, & Albert Jeltsch
Suppl. Text 6: Allele-specific methylation
Allele-specific methylation of amplicon 197_intern from gene DSCR3 in leukocytes.
The A/C SNP (dbsnp, rs764155) and C/T SNP (dbsnp rs764154) were identified. The
positions of all SNP sites are indicated by arrow. Each row corresponds to one clone
of bisulfite PCR products. Each column corresponds to one CpG site in the studied
region. The color codes indicates the different methylation states of each CpG site. As
reported before [16], the C-allele is unmethylated in leukocytes while the A-allele can
be methylated or unmethylated.
DSCR3
T
A
C
C
methylation
unmethylation
unknown
1
Allele-specific methylation has been detected for the CBR1 (amplicon 176_1 and
176_2), C21orf81 (amplicon 23_1 and 23_2) and DSCR3 (amplicon 197_intern)
genes in leukocytes. In the following table the corresponding results obtained in other
tissues are compiled.
176_1
Cell type
176_2
genotype
methylation
methylated allele
HEK293
no del
monophasic m.
G
monophasic unm.
HepG2
no del
biphasic
G
biphasic
Leukocyte
del/no del
biphasic
C/G
biphasic
Fibroblast
no del
monophasic unm.
G
monophasic unm.
Trisomic fibroblast no del
monophasic unm.
C
monophasic unm.
del
genotype
methylation
23_1
Cell type
genotype
methylation
genotype
methylation
A
monophasic unm.
A
monophasic unm.
HepG2
C
monophasic m.
A
monophasic m.
Leukocyte
C
biphasic
Fibroblast
C
monophasic m.
C
monophasic m.
monophasic unm.
A
biphasic
A/C
A/C
biphasic
197 intern
Cell type
genotype
methylation
HEK293
C
biphasic
HepG2
A
monophasic unm.
Leukocyte
A/C
biphasic
Fibroblast
A/C
monophasic unm.
Trisomic fibroblast
A/C
monophasic unm.
C
23_2
methylated allele
HEK293
Trisomic fibroblast
methylated allele
methylated allele
A partially meth.
ASM
Biphasic methylation without SNP
Monophasic methylation with SNP
Abbreviations: del: deletion, m: methylated, unm: unmethylated
2
methylated allele
C