* Resurgent US dollar weighs on energy, mining stocks
* Dell proposes $3.9 bln takeover of Perot Systems
* Futures off: S&P 500 5.3 pts, Nasdaq 9.75 pts, Dow 49 pts
NEW YORK, Sept 21 (Reuters) - U.S. stock index futures fell on Monday as a resurgent U.S. dollar sparked a pullback in global commodity prices and investors sought more definitive signs to justify the market's six-month run-up.
Futures suggested that Wall Street would open down about
half a percent or more, with shares of energy companies and
miners among the notable drags. The energy sector
exchange-traded fund
"The focus right now is a little bit on the dollar," said Rick Meckler, president of investment firm LibertyView Capital Management in New York.
"Now that the dollar is rallying a little bit, it's pushing some technical traders to take some profits (in stocks). I think that's probably the biggest single factor this morning."
S&P 500 futures
Computer maker Dell Inc
The boost from that news, however, was tempered by the rising U.S. dollar. The dollar index, which measures the greenback against a basket of major currencies, rose 0.5 percent. <.DXY>
The benchmark S&P 500 <.SPX> is up 58 percent since hitting a 12-year closing low in early March, partly because of strong second-quarter earnings and optimism that an economic recovery is gaining traction.
That optimism is beginning to come under some strain, however, as investors seek more clarity about the 2010 profit outlook and await hints of how strong results will be for the rest of the year. (Reporting by Ellis Mnyandu; editing by Padraic Cassidy)