Repetitive zinc-binding domains in the protein transcription factor IIIA from Xenopus oocytes.

Abstract

The 7S particle of Xenopus laevis oocytes contains 5S RNA and a 40‐K protein which is required for 5S RNA transcription in vitro. Proteolytic digestion of the protein in the particle yields periodic intermediates spaced at 3‐K intervals and a limit digest containing 3‐K fragments. The native particle is shown to contain 7‐11 zinc atoms. These data suggest that the protein contains repetitive zinc‐binding domains. Analysis of the amino acid sequence reveals nine tandem similar units, each consisting of approximately 30 residues and containing two invariant pairs of cysteines and histidines, the most common ligands for zinc. The linear arrangement of these repeated, independently folding domains, each centred on a zinc ion, comprises the major part of the protein. Such a structure explains how this small protein can bind to the long internal control region of the 5S RNA gene, and stay bound during the passage of an RNA polymerase molecule.

Thionein (apometallothionein) can modulate DNA binding and transcription activation by zinc finger containing factor Spl

“…DNA-binding proteins involved as transcription factors in controlling gene expression [1,2]. Their metal com.…”

Determination of DNA binding specificities of mutated zinc finger domains

“…zinc finger repeats first identified in Xenopus transcription factor Ilia [1,2] and in the Drosophila gap gene KrLippel [3] have been shown to be conserved in several hundred genes analysed from yeast to man [4][5][6][7][8][9]• The zinc finger domains (YxCx2-Cx3FxsLxzHx3HTGEKP) are stabilized by zinc) tetra. hedrally coordinating the 2 conserved cysteine and histidine residues [10].…”

A20, an inhibitor of cell death, self‐associates by its zinc finger domain

“…Since the abundant Xenopus transcription factor IIIA has been reported to contain repeated minidomains with zincbinding property [13], much effort has been made to characterize the rapidly expanding class of zinc finger proteins (reviewed in [8]). It became clear that independent or adjacent zinc fingers can be combined as modules which are able to grip specific DNA sequences, and that they are present in well-established example is the transcription factor Spl which uses Glu-rich regions for self-interaction [14], but the DNAbinding zinc finger region for heterotypic interaction with, e.g., GATA-1 [15] or RelA(p65) [16].…”