Nature 390, 698; 701; 1997

Some of the results reported in this Letter cannot be reproduced. We know that the data on protoplast division described for Figs 1a, c, 2a, band 4, and the corresponding experimental procedures described in the Methods section and the text, are wrong. In fact, the data showing that cAMP can stimulate protoplast division in the absence of auxins are not correct. Hence, we need to retract this paper. We apologize for any misunderstanding that this might have caused.

Note from the Editor: One author, R.W., although concerned with the accuracy of parts of this paper, reserves judgement concerning its retraction and awaits the outcome of further experimentation.