How to narrow down the probe sequence selection range?

The probe design range can be determined by analyzing the promoter sequence. If the range is too broad, initially clone 0.5-1kb fragments into a luciferase reporter vector to verify promoter activity and whether it is regulated by the transcription factor. The core promoter can be identified through serial truncation validation. If the transcription factor under study has a known binding motif, the probe can be selected around that motif site. Alternatively, after performing ChIP or DNA pull-down to find enriched sequences, design segmented probes for validation.