Schmitz, Aaron , Olson, Bradley , Yoder, David , Kadirjan-Kalbach, Deena , Osteryoung, Katherine .
Determining the Chloroplast Division Roles of the Two FtsZ Families in Arabidopsis thaliana.
Plant chloroplasts, organelles of cyanobacterial origin, can divide by fission independent of cellular division. Chloroplast fission requires the presence of the Z-ring, a mid-plastid localized ring on the stromal side of the chloroplast envelope. In bacteria, the Z-ring is composed of a single type of FtsZ and is thought to serve as a cytoskeletal scaffold for recruitment of other division components. In contrast to bacteria, plants have two distinct FtsZ families, FtsZ1 and FtsZ2. The most prominent difference between FtsZ1 and FtsZ2 is at their C-termini; FtsZ2, but not FtsZ1, contains a motif found in bacterial FtsZ proteins that binds other cell division proteins. In Arabidopsis, the contribution to FtsZ1 protein is provided by a single FtsZ1 gene, while FtsZ2 protein is contributed by two FtsZ2 genes. We present data showing that the two AtFtsZ2 genes encode functionally redundant proteins, confirming that there are only two FtsZ families required for normal chloroplast division in Arabidopsis, a scenario likely for other higher plants as well. Recently, we determined that Arabidopsis leaves maintain an FtsZ1 to FtsZ2 ratio of 1:2, and changes in FtsZ levels result in fewer enlarged plastids, indicating a block in chloroplast division. To address the significance of the 1:2 ratio we are altering in vivo FtsZ1:FtsZ2 ratios in Arabidopsis and examining the effects on chloroplast division. Lastly, we are expressing chimeric FtsZ transgenes in wild-type and ftsZ mutant plants to characterize functional units within each FtsZ, including the divergent C-termini. The data obtained from these experiments will be crucial to advancing our understanding of the evolution and assembly mechanisms of the Z-ring in plants.
Log in to add this item to your schedule
1 - Michigan State University, Plant Biology, 166 Plant Biology, East Lansing, MI, 48824, USA
2 - Michigan State University, Biochemistry & Molecular Biology
3 - Michigan State University, Plant Biology
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM