MITOGEN AND GROWTH FACTOR-INDUCED ACTIVATION OF A STAT-LIKE MOLECULE IN CHANNEL CATFISH LYMPHOID-CELLS

This article describes the identification of a putative STAT molecule in the channel catfish (Ictalurus punctatus), the first report of such a molecule in a 'lower' vertebrate. A monoclonal antibody against hum an STAT6 recognizes an similar to 100 kDa molecule that becomes activa ted and translocates to the nucleus upon both growth factor and mitoge n stimulation of catfish leukocytes. This presumed catfish STAT binds the mammalian interferon-gamma activation site, a known motif of mamma lian STAT binding, as shown by electromobility shift assays. Purificat ion of the proteins present in these DNA complexes confirms that the c atfish reactive molecule binds to the interferon-gamma activation site sequence. These results suggest that STAT molecules have been highly conserved in vertebrate evolution. (C) 1998 Elsevier Science Ltd. All rights reserved.