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Abstract Detail


Organelle Biology

Yoder, David [1], Kadirjan-Kalbach, Deena [2], Olson, Bradley [3], Miyagishima, Shin-ya [4], DeBlasio, Stacy [5], Hangarter, Roger [6], Osteryoung, Katherine [2].

Mutations in FtsZ1 affecting chloroplast division.

Plastid division requires proper positioning of a Z-ring composed of the tubulin-like FtsZ. In plants, FtsZ has diverged into two families, FtsZ1 and FtsZ2, which are differentiated by a conserved C-terminal motif, found in most FtsZs that is lacking in FtsZ1. We have investigated the structure-function of FtsZ1 by mapping mutant alleles onto a structural model of AtFtsZ1-1 in Arabidopsis. We have characterized chloroplast morphology, FtsZ levels, and Z-filament morphology in leaves from plants harboring mutant alleles of AtFtsZ1-1. A homozygous T-DNA insertion that is null for FtsZ1 is viable. Three mutants, atftsZ1-1(G267R), atftsZ1-1(R298Q), atftsZ1-1(∆404-433) exhibit reduced levels of FtsZ1, but FtsZ2 accumulation is not altered, suggesting independent regulation of the two families. The semi-dominate allele, atftsZ1-1(G267R), exhibits the most severe plastid division phenotype, harboring a lesion in the predicted T7-loop, but no mutant protein is detected in rings or filaments. Two alleles, atftsZ1-1(D159N) and atftsZ1-1(G366A), exhibit long, sometimes spiral-like FtsZ-filaments, indicating that the dynamics of Z-ring formation are altered. These two mutants differ in their midplastid positioning with atftsZ1-1(D159N) exhibiting a loss of this regulation, but atftsZ1-1(G366A) exhibiting wild-type positioning of Z-rings. Truncation of the C-terminus of FtsZ1 does not significantly alter Z-ring formation and positioning, but does impair chloroplast division. These mutants are the first steps to understanding FtsZ in vivo dynamics, and will be useful for biochemical studies once a plant FtsZ polymerization assay is established.


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1 - Michigan State University, Plant Biology, 166 Plant Biology Bldg. #337, East Lansing, MI, 48824-1312, USA
2 - Michigan State University, Plant Biology
3 - Michigan State University, Plant Biology and Plant Research Lab
4 - RIKEN (Institute of Physical and Chemical Research), Miyagishima Initiative Research Unit
5 - The State University of New York, Stony Brook, Microbiology
6 - Indiana Universtiy, Biology

Keywords:
FtsZ.

Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P18027
Abstract ID:1651


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