New human erg isoforms generated by alternative splicing are transcriptional activators

Area of Science:

• Molecular Biology
• Genetics
• Gene Regulation

Background:

• The erg gene belongs to the ets gene family, encoding transcription factors that bind specific DNA motifs.
• ETS proteins are known to bind the (GGA-A/T) motif and activate transcription.

Purpose of the Study:

• To isolate and characterize novel human erg cDNAs and their protein products.
• To investigate the DNA-binding activity and transcriptional activation potential of different erg isoforms.

Main Methods:

• Isolation of human erg cDNAs from a fetal liver library.
• In vitro transcription-translation to synthesize erg proteins.
• Gel mobility-shift assays to assess DNA-binding specificity.
• Transient transfection assays to evaluate transcriptional activation.

Main Results:

• Three distinct erg cDNAs were isolated, differing in coding sequences and 5' regions.
• Alternative RNA splicing generates these erg isoforms from a single gene.
• All expressed erg isoforms (38, 49, and 55 kDa) specifically bind the ETS DNA motif.
• Erg protein isoforms function as transcriptional activators.

Conclusions:

• The human erg gene generates multiple functional isoforms via alternative splicing.
• These erg isoforms are capable of specific DNA binding and transcriptional activation, highlighting their role in gene regulation.