The line in front of Muller may be someone's "I" for Igor Muller. Muller's signature is neat, though, and the pontil finish he is famous for is like a raised disc. I haven't seen this type of glass come from him.
It is not typical of Murano glass. I would say most likely not Murano. The reverse (clockwise) swirl makes me think of... I can't say it. I don't want to doom the piece before it has a chance. It does not look like a bad piece of glass except for the messy signature.