Keleher G P, Stent G S
Department of Molecular and Cell Biology, Life Sciences Addition, University of California, Berkeley 94720.
Proc Natl Acad Sci U S A. 1990 Nov;87(21):8457-61. doi: 10.1073/pnas.87.21.8457.
The o and p blast cell bandlets of the leech Theromyzon rude, which normally produce two different sets of identifiable cells designated the "O" and "P" fates, respectively, form an equivalence group: in embryos experimentally deprived of their p bandlet, the blast cells of the adjacent o bandlet may "transfate" and take on the P fate. Loss of the p bandlet is not, however, a sufficient condition for transfating of the o bandlet. Rather, loss of the p bandlet allows the o bandlet to shift into ectopic positions, and it is the ultimate position of the o bandlet that mandates which fate--O or P--the blast cells will take on. Therefore, the choice of the pluripotent o blast cells to follow either the O or P developmental pathway depends on their perception of positional cues provided by cells outside the equivalence group rather than on a direct interaction with p blast cell equivalence group members.
水蛭Theromyzon rude的o和p前体细胞带，通常分别产生两组不同的可识别细胞，分别被指定为 “O” 和 “P” 命运，它们形成一个等价组：在实验中被剥夺p带的胚胎中，相邻o带的前体细胞可能会 “转分化” 并呈现P命运。然而，p带的缺失并不是o带转分化的充分条件。相反，p带的缺失使o带能够转移到异位位置，而o带的最终位置决定了前体细胞将呈现哪种命运 —— O或P。因此，多能o前体细胞选择遵循O或P发育途径取决于它们对等价组外细胞提供的位置线索的感知，而不是与p前体细胞等价组成员的直接相互作用。
