The rupee lost 12 paise to trade below 55 level against the dollar on sustained demand of the US currency from importers despite lower dollar overseas. Earlier rupee weakened by 10 paise to 54.98 against the dollar during morning deals today.The rupee opened weak at 55.06 per dollar as against the previous closing level of 54.88 at the Interbank Foreign Exchange Forex market. Dealers said, Persistent dollar demand from importers' pressured rupee sentiment.