Sea urchin USF: a helix-loop-helix protein active in embryonic ectoderm cells.
We previously characterized a DNA-binding factor in nuclear extracts of Strongylocentrotus purpuratus embryos that bound Spec gene promoters, was ectoderm specific, and had properties similar to the vertebrate transcription factor USF. Here we describe a cDNA clone, suUSF, isolated from an S. purpuratus cDNA library, with sequence homology to human USF. Spec gene promoter fragments formed sequence-specific complexes with suUSF, and antibodies against suUSF inhibited binding activity in nuclear extracts. Reaction of USF-site containing probes with filter-bound nuclear proteins demonstrated that suUSF binding activity was enriched in ectoderm cells, and immunoblotting showed a similar ectoderm enrichment. These data demonstrated that suUSF was responsible for the ectoderm-specific activity observed in sea urchin extracts.
Kozlowski
M T
MT
Department of Biochemistry and Molecular Biology, University of Texas M. D. Anderson Cancer Center, Houston 77030.
Gan
L
L
Venuti
J M
JM
Sawadogo
M
M
Klein
W H
WH
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000502:physiology*; D004475:Ectoderm / Q000502:physiology*; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D012617:Sea Urchins / Q000502:physiology*; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic; D051720:Upstream Stimulatory Factors
D004268:DNA-Binding Proteins; D014157:Transcription Factors; D051720:Upstream Stimulatory Factors