The automobiles and parts sector is providing downward pressure on the markets Tuesday on the back of concerns over its exposure to the Japanese car industry. Toyota and Honda have extended plant shutdowns until the weekend, at least.Aerospace and vehicles engineer GKN is also lower on speculation of a bid for French peer Latecoere. The French aerospace firm, which provides doors for Boeing and Airbus, is looking for a buyer, according to reports from a French newspaper. Chinese aviation group AVIC and Dutch aircraft firm Fokker-Stork are also potential bidders. The oil and gas producers are performing well, with blue chip Cairn Energy leading the way.The group is higher even though it has yet to reach an agreement with the Indian authorities over the proposed sale of its Rajasthan assets to Vedanta. Hopes had been raised that Cairn would announce a deal had been struck with today's results, but the group just repeated that the sale of its 51% stake in Cairn India is awaiting approval.Top performing sectors so far todayOil & Gas Producers 8,540.23 +0.31%Industrial Transportation 2,568.82 +0.30%Gas, Water & Multiutilities 4,541.00 +0.11%Construction & Materials 4,210.10 +0.09%Life Insurance 4,422.40 +0.09%Bottom performing sectors so far todayAutomobiles & Parts 4,402.58 -4.17%Chemicals 6,715.29 -1.85%General Industrials 3,195.24 -1.60%Food Producers & Processors 4,828.18 -1.50%Forestry & Paper 5,994.26 -1.50%