H. Ellingerziegelbauer et al., FTZ-F1-RELATED ORPHAN RECEPTORS IN XENOPUS-LAEVIS - TRANSCRIPTIONAL REGULATORS DIFFERENTIALLY EXPRESSED DURING EARLY EMBRYOGENESIS, Molecular and cellular biology, 14(4), 1994, pp. 2786-2797
Orphan receptors of the FTZ-F1-related group of nuclear receptors (xFF
1r) were identified in Xenopus laevis by isolation of cDNAs from a neu
rula stage library. Two cDNAs were found, which encode full-length, hi
ghly related receptor proteins, xFF1rA and B, whose closest relative k
nown so far is the murine LRH-1 orphan receptor. xFF1rA protein expres
sed by a recombinant vaccinia virus system specifically binds to FTZ-F
1 response elements (FRE; PyCAAGGPyCPu). In cotransfection studies, xF
F1rA constitutively activates transcription, in a manner dependent on
the number of FREs. The amounts of at least four mRNAs encoding full-l
ength receptors greatly increase between gastrula and early tailbud st
ages and decrease at later stages. At early tailbud stages, xFTZ-F1-re
lated antigens are found in all nuclei of the embryo.