Currently I am working on Kappa casein gene of Buffalo and cattle. I found greater number Transcription factor binding sites in Buffalo casein gene as compared to cattle..........How I can confirm their role in gene regulation? Can we say if a gene has more TFBS then its expression may increase or decrease according to binding site ?

e.g buffalo casein gene has 30 TATA TFBS and cow has only 5 TATA sites. and also buffalo has 1 YY1 site while cow casein gene has 9 YY1 sites.