SETA: A novel SH3 domain-containing adapter molecule associated with malignancy in astrocytes

Differential display poymerase chain reaction analysis was used to compare five differentiation states of the O-2A progenitor-like cell line CG4: prog enitor cells and cells at 12 h or 4 days after the induction of differentia tion into oligodendrocytes or astrocytes, This led to the identification of 52 sequence tags that were expressed differentially with cellular phenotyp e, One sequence was upregulated during differentiation of CG4 cells and rep resented a novel gene that we named SETA (SH3 domain-containing gene expres sed in tumorigenic astrocytes). This gene encodes an SH3 domain-containing adapter protein with sequence similarity to the CD2AP (CD2 adapter protein) and CMS (Cas ligand with multiple Src homology) genes. SETA mRNA was expre ssed at high levels in the developing rat brain but was barely detectable i n the normal adult rat or human brain. However, SETA mRNA was found in appr oximately one half of the human gliomas tested, including astrocytomas grad es II, III, and IV, as well as oligodendrogliomas, mixed oligoastrocytomas, and human glioma-derived cell lines, A rat glioma generated by treatment w ith the alkylating carcinogen ethylnitrosourea on postnatal day 1 and a der ived cell line also expressed SETA mRNA. Furthermore, in an in vitro model of astrocytoma progression based on p53(-/-) astrocytes, expression of SETA was restricted to cells that are tumorigenic.