US STOCKS-Futures higher, but crude oil weakens
* M&A deal lifts sentiment; UnitedHealth unit to buy Catamaran
* Weakness in oil and strength in dollar could be a concern
* Futures up: Dow 88 pts, S&P 9.25 pts, Nasdaq 28.25 pts
By Ryan Vlastelica
NEW YORK, March 30 (Reuters) - U.S. stock index futures rose on Monday, pointing to a second straight daily gain as a trio of M&A deals lifted sentiment after a recent bout of weakness.
* Despite that, energy shares could come under pressure as crude oil fell sharply, due to a possible deal with Iran that could bring an end to sanctions and allow an increase in the country's oil exports. Crude oil fell 1.8 percent to $47.94 per barrel.
* Separately, an increase in the U.S. dollar could weigh on multi-nationals.
* Both the dollar and commodity prices have given investors reason to be cautious of late, especially going into the first-quarter earnings season, where traders will look to see how much oil prices and the strong U.S. dollar will impact corporate bottom lines. Last week, the S&P 500 fell 2.2 percent, the Dow lost 2.3 percent and the Nasdaq declined 2.7 percent.
* In deal news, OptumRx Corp, a unit of UnitedHealth Group , agreed to buy pharmacy benefit manager Catamaran Corp in a deal worth $12.78 billion. Shares of UnitedHealth, a Dow component, rose 2.7 percent to $121.60 before the bell while U.S. shares of Catamaran added 26 percent to $60.75. Continuación...