Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published August 1993 | public
Journal Article

SpOct, a Gene Encoding the Major Octamer-Binding Protein in Sea Urchin Embryos: Expression Profile, Evolutionary Relationships, and DNA Binding of Expressed Protein

Abstract

We have characterized a sea urchin gene, SpOct, that encodes a 78-kDa POU-domain protein related to mammalian Oct-1 and Oct-2. The SpOct protein binds octamer elements in the promoters of the α H2B (Bell et al., 1992, Dev. Biol. 150, 363-371) and CylIIa actin genes, and it closely resembles the major octamer-binding activity obtained from sea urchin blastula nuclear lysates in the size of its DNase I footprint on a canonical octamer element and in its relative binding affinity (K_r) for the octamer element versus poly(dAT) (1.4 × 10^4). Moreover, partial protein sequences obtained from affinity-purified octamer-binding protein match sequences present in SpOct. These data suggest that SpOct is closely related to, if not identical with, the major octamer-binding activity in blastula nuclear extracts. RNA gel blots reveal four forms of SpOct mRNA, ranging in size from 4 to 12 kb. They are regulated coordinately in the embryo: all are present in the unfertilized egg, increase 28-fold in amount by the 8-hr blastula stage, and decline 6-fold by the 12-hr blastula stage. The same four size classes of SpOct mRNAs are present in several adult tissues, although their relative amounts vary. The temporal profile of SpOct mRNA expression in embryos closely resembles that of the α histone H2B gene. Our previous work (Bell et al., 1992) showed that expression of the α H2B gene in blastula-stage embryos was entirely dependent on an octamer element. Together, these data strongly suggest that SpOct may be the key regulator of the a H2B gene.

Additional Information

© 1993 Academic Press, Inc. Accepted March 4, 1993. This work was supported by NIH Grant HD18582 and NCI Institutional Grant 5P30-CA14089-14 (R.M.), NSF Grant DCB8912530 (F.J.C.), NIH Grant HD05753, and the Ralph M. Parsons Foundation (E.H.D.). B.R.C. was partially supported by a fellowship from the California Foundation for Biomedical Research and a Smoot fellowship from USC. J.B. was supported by NCI Training Grant 5-T32-CA09569-03 and a grant from the Wright Foundation, J.A.C. by NIH Training Grant HD07257, and M.G.H. by NSF grant STCDIR8809719 to L. Hood. We thank Michael Stallcup and Frank Sangiorgi for critical reviews of the manuscript, Sonia Dobias for help in plaque-purifying the SpOct clones, and Lynn Williams for the synthesis of oligonucleotides. Finally, we acknowledge the members of the Southwest Sea Urchin Society for many helpful discussions.

Additional details

Created:
August 20, 2023
Modified:
October 18, 2023