Fig. 3. Plant Spc98p and 
-tubulin localization at the surface of isolated
tobacco BY-2 nuclei after in vitro MT nucleation. (A) Mid-section of a
confocal z-stack labeled with anti-Spc98pB/Alexa 488. (B) Top section at the
surface of the same nucleus labeled with anti-
-tubulin/Alexa 568. (C)
Merged mid-section showing the perinuclear sites of MT nucleation. (D)
Midsection of a nucleus revealed with anti--tubulin/Alexa 488. (E)
Top-section at the surface of the same nucleus labeled with
anti--tubulin/Alexa568. (F) Merged mid-section using a Zeiss LSM 510
microscope. Insets, Nomarski images of the isolated nuclei. (G) Inhibition of
MT nucleation by preincubation with anti--tubulin antibodies. Merged
projection of an entire nucleus. No MTs are polymerized. (H) Inhibition by
anti-Spc98pB antibodies: a few short MT remnants are observed at the surface
of the nucleus in this merged projection, but no MT nucleation was observed.
(I) Following a competition assay for 1 hour with preincubation using
anti-Spc98pB antibodies and Spc98pB peptide, nucleation was not inhibited.
Bar, 10 µm.
