DIRAS3 (DIRAS family, GTP-binding RAS-like 3, ARHI, NOEY2) is a ras-related gene which acts as a
growth regulator in ovarian and breast cancers (Yuan
J, et al 2003).
It is reported to be paternally expressed and maternally 'imprinted' (Yu
Y et al 1999). However the data are minimal. Monoallelic expression was detected
in 4/4 informative samples which included two cancer cell lines, one ovarian surface epithelium
primary culture and one normal breast epithelium sample. In the last sample only, the expressed
allele could be identified and was paternal. In three families, using an intron 1 (AT)n
polymorphism, only the maternal DNA allele could be amplified in all six offspring after genomic DNA
was digested by the methylation-sensitive restriction enzyme BstUI. In another family, only the
maternal allele at position -750 bp could be amplified after BstUI digestion.
Methylation sensitive Southern blotting showed evidence of partial methylation in the promoter CpG
island in normal tissues (Luo
RZ et al 2001).
It has three CpG islands.