The founder of Mount Pleasant biotechnology company GenPhar, who is accused of illegally funneling campaign contributions to a U.S. senator, took the stand today in federal court in Charleston.

Jian-Yun “John” Dong, 55, has been in trial all week to fight the allegations that, between 2007 and 2009, he worked to circumvent federal laws to contribute money to Sen. Lindsey Graham and his political action committee. He’s also accused of witness tampering and lying to investigators.

During his testimony, Dong told the jury he did not know what he was doing was illegal. He spoke of his time in China, where he said he was persecuted for his beliefs, before coming to the United States. He repeatedly referred to the campaign contributions as a “privilege.” Dong became emotional on the stand when he spoke of his now estranged wife, Danher Wang, who testified against him earlier this week. He also expressed regret that his “stupid mistake” cost the jobs of GenPhar employees and led to the loss of federal projects, he said.

Prosecutors have said that Dong convinced former employees to serve as proxies for his donations because he had already reached the maximum limit of contributions he could make to Graham.

Graham is not accused of any wrongdoing and prosecutors said Graham and members of his staff were not aware the contributions were tainted.

Dong believed contributions to Graham would lead to more federal funds through grants and earmarks for GenPhar, which was developing vaccines for the Ebola and Marburg viruses, prosecutors said. Dong told the jury that wasn’t true and said he donated to Graham because he wanted to support a leader that he shared similar beliefs with.

Dong’s attorneys indicated he would be the only witness they’d call. His testimony wrapped up Thursday afternoon.

Throughout the week, prosecutors called several witnesses to testify, including former employees of GenPhar and Wang, 53, who pleaded guilty last week to her role in the alleged campaign contribution scheme.

The jury will likely begin deliberating Friday afternoon. Closing arguments are expected to begin Friday morning.

Read more in future editions of The Post and Courier.

Reach Natalie Caula at 937-5594 or Twitter.com/ncaula.