A director of Dow Jones has quit in protest at Rupert Murdoch's $5bn (£2.5bn) bid for the firm, saying it is a threat to its journalistic values.
The Wall Street Journal was founded in 1889
German executive Dieter von Holtzbrinck said he was "very worried" about the impact of the bid on the Wall Street Journal and its editorial independence.
The show of dissent follows a decision by the firm's board to endorse News Corporation's bid on Wednesday.
This must be approved by the Bancroft family, which controls the firm.
News Corporation has pledged to fully respect and maintain the Wall Street Journal's independence and that of the firm's other business news services.
But this has not been enough to reassure Mr von Holtzbrinck, whose resignation was revealed in a report by the firm to stock market regulators.
In a letter to his fellow directors, Mr von Holtzbrinck said the News Corp takeover bid was "very generous in financial terms".
But he spoke of his concern that the firm's "unique journalistic values will long-term strongly suffer after the proposed sale".
"I cannot prove my worries are right," he added. "I can only refer to News Corporation practices in the past."
News Corporation has not commented on his assertions.
Some members of the Bancroft family are known to harbour strong reservations about the deal although not all are thought to be opposed.
The family, who control 64% of the firm's voting shares, is expected to meet on Monday to consider the bid.
Mr von Holtzbrinck is chairman of the supervisory board of family firm von Holtzbrinck, which owns a number of leading German newspapers.