NEW YORK ( TheStreet) -- U.S. stock futures were signaling a weaker Wall Street open Tuesday as election turmoil in Greece and a changing of the guard in France weighed on global equities. European stocks were slipping in early trading, while Asian stocks posted modest gains. Japan's Nikkei 225 index gained 0.7% to close at 9,181.65. Stocks finished mixed Monday as Wall Street reacted with restraint to the shifting political landscape in Europe following weekend elections in France and Greece. The Dow Jones Industrial Average fell 0.23% to finish at 13,008.53. Walt Disney ( DIS) is expected by analysts Tuesday to post fiscal second-quarter earnings of 55 cents a share on revenue of $9.56 billion. The media and entertainment giant, which scored big with the release of The Avengers over the weekend, posts results after the markets close. Disney shares have risen nearly 15% year to date. McDonald's ( MCD) is expected Tuesday to post sales results for April. The world's largest fast-food chain said last month it expected global same-store sales in April to rise about 4%. Sales jumped 7.3% in the first quarter. Rick Santorum, the former presidential hopeful, is backing Mitt Romney in his bid to unseat President Obama. "The primary campaign certainly made it clear that Gov. Romney and I have some differences. But there are many significant areas in which we agree," Santorum wrote in an email late Monday. "Above all else, we both agree that President Obama must be defeated. The task will not be easy. It will require all hands on deck if our nominee is to be victorious. Gov. Romney will be that nominee and he has my endorsement and support to win this the most critical election of our lifetime." Santorum, the former Pennsylvania senator, held a private meeting with Romney Friday in Pittsburgh. Yahoo! ( YHOO) CEO Scott Thompson apologized for inaccuracies in his bio, and said he remains focused on turning around the Internet company. "We have all been working very hard to move the company forward, and this has had the opposite effect," Thompson wrote. "For that, I take full responsibility, and I want to apologize to you." Yahoo's board has begun investigating the circumstances that led to a bogus computer science degree being including on Thompson's bio, The Associated Press reported. -- Written by Joseph Woelfel >To contact the writer of this article, click here: Joseph Woelfel >To submit a news tip, send an email to: firstname.lastname@example.org.