Sequence-specific and length-dependent interaction of C2H2 zinc fingers and (TA)(n) microsatellites

A possible function for microsatellite elements still remains elusive. Here we demonstrate that (TA)(n) microsatellites can be recognized in vivo in transient assays by a combination of naturally occurring C2H2 zinc fingers with high affinity that depends on specific protein-DNA contacts. This interaction results in an upregulation of the basal transcription level, when (TA)(n) elements are placed upstream of a minimal promoter. Upregulation depends on the length of the element. Our results suggest that specific interaction of transcription factors with microsatellite sequences may underlie effects on transcriptional regulation exerted by these sequences. Identification of such interactions would be a first step towards understanding the function and evolution of microsatellite elements.