Biophysical Journal 87 2

Cover picture: Time-courses for transfer of three Alexa dyes through different homotypic gap junction channels in Xenopus oocyte pairs. Images were taken at the times indicated on the left after Alexa 350, 488, or 594 microinjection into the left oocyte (donor) of each pair. Oocytes were injected 16–24 h earlier with antisense oligo to XeCx38 without (-/-) or with the connexin cRNA indicated along the top (e.g., Cx37/Cx37). Different connexins showed variable permeability to the dyes (Cx37 was the least permeable). In addition, as the size of the dyes increased, greater selectivity was evident, so that only Cx32 and Cx43 channels passed the largest dye Alexa 594 efficiently. Finally, Alexa 350 was found to selectively leak through hemichannels of all connexins except Cx37. Color assignment of digitized fluorescent images is based on pixel intensity, proportional to fluorescent probe concentration. See the article by Weber et al. on p. 958.