5 splice site(5剪接位点): the exon- intron boundary at the 5 end of the intron 3’ splice site(3剪接位点):the exon-intron boundary at the 3 end of the intron Branch point site(分枝位点):anA close to the 3 end of the intron which is followed by a polypyrimidine tract(Py tract)◼ 5’splice site (5’剪接位点): the exon￾intron boundary at the 5’ end of the intron ◼ 3’ splice site (3’剪接位点): the exon-intron boundary at the 3’ end of the intron ◼ Branch point site (分枝位点): an A close to the 3’ end of the intron, which is followed by a polypyrimidine tract (Py tract)