Christine, I think you might be right about the 'signature'...
As for the seller, something about him is very fishy -- I wrote to him, asking about the water stain and requesting that he wash the vase and send me more pictures, including a better one of the signature. He refused, saying "the vase is in very good condition, just a little dirty. I kept flowers in it for 2 months, hence the stains. I am selling it as it is and I will not wash it." Aha, and he ignored my request to send me a picture of the uranium vase 'glowing'. Highly polite and professional behavior
If the vase is, as the seller describes, "old, rare... signed...", why on earth would he even use it? Heck, use it and leave water in it, and then not bother to wash it? I think there is a little "BS" in his story.
So the vase is not uranium, TOLETLE is not the maker's signature, and I strongly doubt the vase is "old, rare and in very good condition"
End of story