WHIRLY Transcription Factor Family
Members of the Whirly family of proteins are found throughout the plant kingdom and are predicted to share the ability to
bind to single-stranded DNA. Arabidopsis and potato Whirly orthologs act as transcription factors that regulate defense gene
expression; the Arabidopsis Whirly protein AtWhy1 contributes to both basal and specific defense responses. Analysis of the
crystal structure of potato StWhy1 has provided insight into the DNA-binding mechanism of this family of proteins, their
mode of action and possible autoregulation. There is evidence to suggest that Whirly proteins might play roles in processes
other than defense responses and could function in the chloroplast as well as in the nucleus.
This Whirly family is also named PBF-2-like family.
Elicitor-induced activation of the potato pathogenesis-related gene PR-10a requires a 30-bp promoter sequence termed the ERE
(elicitor response element) that is bound by the nuclear factor PBF-2 (PR-10a binding factor 2). In this study, PBF-2 has
been purified to near homogeneity from elicited tubers through a combination of anion-exchange and DNA affinity
chromatography. Evidence demonstrates that inactive PBF-2 is stored in the nuclei of fresh tubers and becomes available for
binding to the ERE upon elicitation. A protein with an apparent molecular mass of 24 kD (p24) is a DNA binding component of
PBF-2. A cDNA encoding p24 has been cloned and encodes a novel protein with a potential transcriptional activation domain
that could also act as a single-stranded DNA binding domain. Both PBF-2 and the cDNA-encoded protein bind with high affinity
to the single-stranded form of the ERE in a sequence-specific manner. The inverted repeat sequence of the ERE,
TGACAnnnnTGTCA, is critical for binding of this factor in vitro and for PR-10a expression in vivo, supporting the role of
PBF-2 as a transcriptional regulator.
Notes: WHIRLY is missed in PlnTFDB.
12 predicted putative Whirly TF peptide,
CDS, and cDNA sequences;
blast HSP, and multiple sequence alignment in
Soy - TFKB.
8 Whirly protein
and DNA
sequences with
annotations for soybean in PlantTFDB. Most are partial sequences.
Last updated by Dr. Jeff Chen on July 20, 2009.