April 6 (Reuters) - The S&P 500 and the Dow opened lower on Tuesday after closing at record highs in the previous session, as investors locked in some gains ahead of a reading of U.S. job openings later in the day. The Dow Jones Industrial Average fell 27.2 points, or 0.08%, at the open to 33,500.02. The S&P 500 fell 2.3 points, or 0.06%, at the open to 4,075.57, while the Nasdaq Composite dropped 23.9 points, or 0.17%, to 13,681.671 at the opening bell. (Reporting by Shivani Kumaresan in Bengaluru; Editing by Arun Koyyur)