Table I.

Localization of Inn1-GFP in wild-type and cytokinesis mutant strains

StrainPercentage of cells with the indicated localization pattern
Faint or no signalSymmetric line or two dotsaOne dot (center)bAsymmetric dot or linebOtherc
myo1Δ [YCp50-MYO1]62d271100
myo1Δ422211169
Wild type68d201120
hof1Δ561512170
cyk3Δ3554920
hof1Δ cyk3Δe542412100
  • After transformation of each strain with plasmid YCp111-CDC3-CFP and growth to exponential phase in SC-Leu or SC-Leu-Ura liquid medium at 24°C, cells with split septin rings were scored in strains LY1364 (myo1Δ INN1-GFP [YCp50-MYO1]; n = 81), YEF5293 (myo1Δ INN1-GFP; n = 95), LY1314 (INN1-GFP; n = 66), LY1328 (hof1Δ INN1-GFP; n = 94), LY1321 (cyk3Δ INN1-GFP; n = 117), and LY1325 (hof1Δ cyk3Δ INN1-GFP; n = 50). Strains LY1328 and LY1325 were first cured of their URA3 HOF1 plasmids by growth on an FOA plate. The patterns of Inn1 localization were assessed by 3D microscopy as described in Materials and methods (Videos 1–7).

  • a Both types of images presumably represent views of a more or less normal ring of Inn1-GFP.

  • b If an Inn1-GFP dot was positioned within one third of the diameter of the Cdc3-CFP ring from either side, it was scored as asymmetric; if within the middle one third of the neck, it was scored as one dot (center). Asymmetric lines presumably represent asymmetrically contracting rings.

  • c Other indicates a variety of asymmetric patterns, including asymmetries along the mother–bud axis (presumably related to the misdirected membrane invagination that occurs in many myo1Δ cells; unpublished data).

  • d The higher number of cells with faint or no signal in wild-type strains, in comparison with myo1Δ and cyk3Δ strains, presumably reflects the more efficient completion of cytokinesis and corresponding rapid disappearance of the Inn1-GFP signal in wild-type cells.

  • e Like several other mutants (see Introduction and Results), hof1Δ cyk3Δ strains appear to be inviable on rich medium but can be cultured on SC medium.