SoPIN1, PIN1a, and PIN1b localization during lemma initiation.

<p>Internal confocal maximum projections showing cellular localization of SoPIN1, PIN1a, PIN1b and DR5 in I2-P1 lemma primordia. (A) SoPIN1. Inset shows an alternate confocal section of the I1 primordium with an epidermal (L1) periclinal cell division. (B) SoPIN1 and DR5 localization in an alternate sample at an earlier stage than (A). (C) PIN1a and DR5. (D–E) PIN1b, (D) at earlier stage than (E). Double arrow shows the forming I1 midvein trace. (F), same dataset as (C), DR5 channel only. Large arrow shows region of lowered DR5 expression along the P1 midvein spanned by PIN1a, see (C). (G–H) I1 details of SoPIN1 and DR5 localization in two different samples, (H) at a later stage than (G). (I) PIN1a in I2 at similar stage as (H). Note polarization towards the center of the meristem, surrounding the L2 periclinal division. (J–L) DR5 expression is reduced in areas of high PIN1b expression. (J) PIN1b, (K) DR5, and (L) merged images of a P1 lemma primordium. Large arrow in (K) shows region of reduced DR5 in the PIN1b midvein domain. Double arrow in (J) and (L) shows beginning of PIN1b expression during formation of the I1 midvein. (M) Detail of SoPIN1 and DR5 in P1 midvein. (N) Detail of PIN1a and DR5 in P1 midvein. Images in A, C, E, F are details of same samples as <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003447#pcbi-1003447-g002" target="_blank">Figure 2C–H</a>. Detail area for (A–F) is indicated by the dashed box in <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003447#pcbi-1003447-g001" target="_blank">Figure 1A</a>. See Figures S5, S6, S7, S8, S9, S10 for split DR5 and PIN channel images of (B), (C), (G), (H), (M), and (N). Ratios below each figure label indicate the number of times a given phenomena discussed in the text was observed out of the total imaged. Primordia I2, I1 and P1 are labeled. Asterisks show SoPIN1 convergence points in (A), (B), (G), (H), and (M). Small arrows indicate inferred polarity of PIN. Scale Bars: 10 µm.