Differentially spliced erg-3 product functions as a transcriptional activator

ets oncogene superfamily consists of a family of transcriptional factors that functions as activators and/or repressors. Previously, we have identified a member of this ets superfamily namely erg, ets related gene. erg gene was shown to code for at least two proteins erg-1 and erg-2 because of alternative splicing and alternative usage of initiation codon. In this report we show that erg gene codes for an additional erg variant protein, erg-3 as a result of differential splicing which results in the insertion of 24 amino acids in the coding region of erg-2 protein. RNAase protection analysis revealed that erg-3 transcripts are expressed in a variety of cells. Erg-3 was also found to activate the transcription of the reporter TK-CAT gene linked to erg target sequences suggesting that erg-3 codes for a sequence specific transcriptional activator.