Kinetic behaviour of WT1's zinc-finger domain in binding to the alpha-actinin 1 mRNA
Arch Biochem Biophys 497, 21-27 (2010) - PMID: 20193655
Authors: Elmar Nurmemmedov, Raymond K Yengo, Michael R Ladomery, Marjolein MGM Thunnissen
The zinc finger transcription factor Wilms Tumour protein (WT1) is known for its essential involvement in the development of the genitourinary system as well as of other organs and tissues. WT1 is capable of selectively binding either DNA or mRNA targets. A KTS insertion due to alternative splicing between the zinc fingers 3 and 4 and an unconventional zinc finger 1 are the unique features that distinguish WT1 from classical DNA-binding C2H2-type zinc finger proteins. The DNA binding characteristics of WT1 are well studied. Due to lack of information about its native RNA targets, no extensive research has been directed at how WT1 binds RNA. Using surface plasmon resonance, this study attempts to understand the binding behaviour of WT1 zinc fingers with its recently reported and first putative mRNA target, ACT34, whose stem-loop structure is believed to be critical for the interactions with WT1. We have analysed the interactions of five WT1 zinc finger truncations with wild-type ACT34 and four variants. Our results indicate that WT1 zinc fingers bind ACT34 in a specific manner, and that this occurs as interplay of all four zinc fingers. We also report that a sensitive kinetic balance, which is equilibrated by both zinc finger 1 and KTS, regulates the interaction with ACT34. The stem-loop and the flanking nucleotides are important elements for specific recognition by WT1 zinc fingers.
Keywords: WT1,transcription factor,zinc finger,surface plasmon resonance,RNA-binding,ACT34,alpha-actinin 1