A method of identifying transcription factors comprising providing cells
with a nucleic acid sequence at least comprising a sequence CACCT (SEQ ID
NO:1) as bait for the screening of a library encoding potential
transcription factors and performing a specificity test to isolate said
factors. Preferably, the bait comprises twice the CACCT (SEQ ID NO:1)
sequence, more particularly the bait comprises one of the sequences
CACCT-N-CACCT (a first SEQ ID NO:1 and a second SEQ ID NO:1 separated by
N), CACCT-N-AGGTG (SEQ ID NO:1 and SEQ ID NO:3 separated by N),
AGGTG-N-CACCT (SEQ ID NO:3 and SEQ ID NO:1 separated by N), or
AGGTG-N-AGGTG (a first SEQ ID NO:3 and a second SEQ ID NO:3 separated by
N), wherein N is a spacer sequence. The transcription factors identified
using the methods of the invention include separated clusters of zinc
fingers, such as, for example, a two-handed zinc finger transcription
factor. Also, at least one such zinc finger transcription factor,
denominated as SIP1, induces tumor metastasis by down regulation of the
expression of E-cadherin. Compounds interfering with SIP1 activity can
thus be used to prevent tumor invasion and metastasis.