ALBANY — David Johnson has become well acquainted with the Fifth Amendment.

The former aide, whose domestic-violence case helped sink Gov. Paterson’s election bid, invoked his right against self-incrimination during an investigation into the Aqueduct-casino boondoggle, sources said.

Johnson refused to answer questions under oath several weeks ago and invoked the Fifth during separate state probes into whether administration officials intervened in his case and whether he wrongly helped the governor secure World Series tickets, the sources told The Post.