To unravel the mechanism of HRSL3 tumor suppressor action, we performed a yeast two-hybrid screen and identified the alpha-isoform of the regulatory subunit A of protein phosphatase 2A (PR65alpha) as a new interaction partner of HRSL3.
Nucleotide sequence analysis demonstrated that the RIG1 gene was similar to a recently-isolated TIG3 gene, and displayed 54% nucleotide sequence homology with a type II tumor suppressor gene H-REV-107-1.
Additionally, the type II tumor suppressor HRASLS3, which has a role in mitogen-activated protein kinase (MAPK) pathway suppression, was constitutively elevated in cell lines resistant to the senescence effects compared to their sensitive counterparts.
H-REV107 is a member of the HREV107 family of class II tumor suppressor genes and a growth inhibitory Ras target gene that suppresses cellular growth, differentiation, and apoptosis.
These results demonstrate down-regulation of the class II tumour suppressor H-REV107-1 in human ovarian carcinomas and suggest an involvement of H-REV107-1 in interferon-dependent cell death.