scholarly journals Gene regulatory factors of the sea urchin embryo. II. Two dissimilar proteins, P3A1 and P3A2, bind to the same target sites that are required for early territorial gene expression

Development ◽  
1991 ◽  
Vol 112 (1) ◽  
pp. 351-364 ◽  
Author(s):  
C. Hoog ◽  
F.J. Calzone ◽  
A.E. Cutting ◽  
R.J. Britten ◽  
E.H. Davidson

Previous work demonstrated that a negative regulatory interaction mediated by factor(s) termed ‘P3A’ is required for correct territory-specific gene expression in the sea urchin embryo. A probe derived from a P3A target site in the skeletogenic SM50 gene of Strongylocentrotus purpuratus was used to isolate a cDNA clone coding for a factor that binds specifically to this site. This factor, called P3A1, contains two sequence elements that belong to the Zn finger class of DNA-binding motifs, and in these regions is most closely similar to the Drosophila hunchback factor. The P3A1 factor also binds to a similar target sequence in a second gene, CyIIIa, expressed in embryonic aboral ectoderm. Another sea urchin embryo protein factor, P3A2, has been isolated by affinity chromatography and cloned, as described in Calzone et al. Development 112, 335–350 (1991). P3A2 footprints the same target sites in the SM50 and CyIIIa genes as does P3A1, but lacks the Zn finger sequence motifs and in amino acid sequence is almost entirely dissimilar to P3A1. A deletion analysis of P3A2 delimited the DNA-binding region, revealing that five specific amino acids in the first P3A1 finger region and four in the second P3A1 finger region are also present in equivalent positions in P3A2. The P3A1 and P3A2 factors could function as regulatory antagonists, having evolved similar target specificities from dissimilar DNA-binding domains.

1985 ◽  
Vol 109 (2) ◽  
pp. 418-427 ◽  
Author(s):  
Martin Nemer ◽  
David G. Wilkinson ◽  
Elizabeth C. Travaglini

Development ◽  
1991 ◽  
Vol 112 (1) ◽  
pp. 335-350 ◽  
Author(s):  
F.J. Calzone ◽  
C. Hoog ◽  
D.B. Teplow ◽  
A.E. Cutting ◽  
R.W. Zeller ◽  
...  

The P3A2 regulatory protein interacts with specific sites in the control region of the CyIIIa actin gene. Previous studies showed that this interaction is required to confine expression of a CyIIIa.CAT fusion to the aboral ectoderm, the embryonic territory in which CyIIIa is normally utilized. P3A2 also binds specifically to similar target sites located in the regulatory region of the SM50 gene, which is expressed only in skeletogenic mesenchyme lineages. The P3A2 factor was purified by affinity chromatography from nuclear extracts of 24 h sea urchin embryos, and partial peptide sequences were used to isolate a cDNA clone encoding the complete protein. There are no significant similarities between P3A2 and any other protein in existing sequence data bases. P3A2 thus includes a novel type of DNA-binding domain. To examine the differential utilization of P3A2 in CyIIIa and SM50 genes, we measured the specific affinity of this protein for the various target sites in the regulatory DNAs of each gene, and identified the core target site sequences. The stability of P3A2 complexes formed with SM50 target sites is 50–100 times greater than that of the complexes formed with CyIIIa target sites, though the factor binds to very similar core sequence elements. P3A2 is one of at least twelve different proteins whose interaction with CyIIIa regulatory DNA is required for correct developmental expression. The results reported demonstrate that it might be possible to purify most of these regulatory proteins, or any other specific DNA-binding proteins of the sea urchin embryo, by using the simple procedures described for P3A2.


1985 ◽  
Vol 50 (0) ◽  
pp. 321-328 ◽  
Author(s):  
E.H. Davidson ◽  
C.N. Flytzanis ◽  
J.J. Lee ◽  
J.J. Robinson ◽  
S.J. Rose ◽  
...  

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