Worm Breeder's Gazette 9(3): 69

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The Heptamers in the Vitellogenin Promoters: An Update

E. Zucker, J. Cane and T. Blumenthal

Figure 1

There are two heptamers repeated multiple times upstream of the C. 
enin genes. In order to obtain evidence for 
or against the functional importance of these heptamers we have 
investigated their evolutionary stability. We sequenced the homologous 
promoters from C. briggsae and the only C. 
enin promoter remaining unsequenced vit-3. 
This brings the total number of nematode vitellogenin promoters 
sequenced to eleven. The data are shown schematically in the Figure. 
Box 1 TGTCAAT, is shown as rectangles; Box 2 CTGATAA is shown as ovals.
In general the heptamers have beer very highly conserved while the 
sequences between them have diverged considerably. In particular there 
has been strong conservation of the Box 1 heptamers centered at -45 (
just upstream of the TArA box)those at -180 (which we have suggested 
may be at the 5' border of the promoter regions) and at least one Box 
1 between -45 and -180. In each case the locations and sequences of at 
least these Box 1 heptamers and at least one Box 2 heptamer per 
promoter have been conserved. This data strongly supports the 
hypothesis that Box 1 and Box 2 are involved in vit promoter function. 
We are initiating experiments to determine the relationship between 
the two heptamers and the three modes of regulation: sex stage and 
We have noted previously the presence of Box 2 in the vertebrate 
vitellogenin promoters. Klein-Hitpass et al. (Cell 46 1053) have 
tested the idea that this heptamer plays a role in Xenopus 
vitellogenin gene induction by estrogen in a transient expression 
assay using a human mammary cell line. They present evidence that it 
is a binding site for an activator protein required for estrogen 
induction but not the site for estrogen receptor itself. They name it 
the 'elegans box'.  Does this mean that the regulatory protein that 
binds to this sequence in the C. e is also 
present in human mammary cells?

Figure 1