Nuclear factor I stimulates transcription of the adenovirus 12 E1A gene in a cell-free system

Binding to the cis-acting region of NF-I-like protein and/or NF-III-like protein was previously suggested to be responsible for the preferential stimulation of transcription from distal start-site of the adenovirus 12 E1A gene in a cell-free system. In this study, nuclear extracts of Ehrlich ascites tumor cells depleted of NF-I-like protein were found to lose activity to stimulate the E1A gene transcription. This activity was recovered when NF-I purified from HeLa cells with no contamination of NF-III was supplemented. It is thus evident that NF-I is involved in stimulating distal transcription of the adenovirus 12 E1A gene. Moreover, activities for both stimulating the E1A gene transcription and binding to a region recognized by NF-I did not apparently exist in nuclear extracts of a cell line expressing the adenovirus 12 E1A gene. These results suggest that transcription of the adenovirus 12 E1A gene may possibly be autoregulated at least in part through modulation of the activity of NF-I.