DUBAI - A grandson of the leader of Iran's 1979 revolution, Ayatollah Ruhollah Khomeini, is expected to seek election early next year to the body that chooses Iran's supreme leader and is said to have the cautious blessing of the incumbent, Ayatollah Ali Khamenei.Registration opens on Thursday for the election that is likely to see the first member of the family of Iran's revolutionary founder test his popularity at the ballot box.Hassan Khomeini's expected candidacy in February's vote is already causing a heated row between hardliners and moderates, since membership of the assembly would place him at the top of Iran's political establishment. Some say he has his eyes eventually on the top job. Hassan Khomeini, 43, a mid-ranking cleric, intends to nominate himself in coming days, family friends and sources close to him told Reuters.With powerful backers he is well-placed to win a seat on the 88-member assembly.With both Khomeini's sons now dead, Hassan Khomeini, who has close links with reformists, is seen as the main family heir, and his decision to enter politics has set Tehran's political world abuzz.A source close to Khomeini said he had received the approval of the incumbent, Ayatollah Ali Khamenei, at a meeting last week at which the Supreme Leader cautioned that he should be careful not to bring his grandfather's name into disrepute. Khamenei told him: "There is no problem (with your nomination), only be careful not to damage Khomeini's name and respect," the source said.Khamenei is 76, so the new assembly is expected to play a significant role in choosing his successor since its members are only elected every eight years.Hassan Khomeini is close to the pragmatic, centrist President Hassan Rouhani, whose popularity has risen thanks to a nuclear deal his government struck with world powers in July.Rouhani and his powerful ally, Akbar Hashemi Rafsanjani, are hoping to cash in on that popularity to help like-minded politicians win a majority in the assembly and in a parliamentary election that will be held on the same day.Rouhani and Rafsanjani, veteran members of the assembly, hope an alliance they appear to be forming with the young Khomeini will bring a breath of fresh air to their camp."Hassan Khomeini is a progressive theologian, especially when it comes to music, women's rights and social freedom," one of his close friends told Reuters on condition of anonymity."He closely follows trends on social media and reads the papers. He is interested in Western philosophy as much as Islamic thoughts," he added.The friend said Khomeini had spent time in Malaysia in order to improve his English. At home, he used to sit in the ordinary seats at football matches rather than the VIP section.