T. Fukushige et al., Direct visualization of the elt-2 gut-specific GATA factor binding to a target promoter inside the living Caenorhabditis elegans embryo, P NAS US, 96(21), 1999, pp. 11883-11888
Citations number
21
Categorie Soggetti
Multidisciplinary
Journal title
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
In analyzing the transcriptional networks that regulate development, one id
eally would like to determine whether a particular transcription factor bin
ds directly to a candidate target promoter inside the living embryo. Proper
ties of the Caenorhabditis elegans elt-2 gene, which encodes a gut-specific
GATA factor, have allowed us to develop such a method, We previously have
shown, by means of ectopic expression studies, that elt-2 regulates its own
promoter. To test whether this autoregulation is direct, we fused green fl
uorescent protein (GFP) close to the C terminus of elt-2 in a construct tha
t contains the full elt-2 promoter and the full elt-2 zinc finger DNA bindi
ng domain; the construct is expressed correctly (i.e., only in the gut line
age) and is able to rescue the lethality of an elt-2 null mutant. Multicopy
transgenic arrays of this rescuing elt-2::GFP construct were integrated in
to the genome and transgenic embryos were examined when the developing gut
has 4-8 cells; the majority of these embryonic gut nuclei show two discrete
intense foci of fluorescence. We interpret these fluorescent foci as the r
esult of ELT-2::CFP binding directly to its own promoter within nuclei of t
he developing gut lineage. Numerous control experiments, both genetic and b
iochemical, all support this conclusion and support the specificity of the
binding. The approach should be applicable to studying other transcription
factors binding target promoters, all within the living C, elegans embryo.