Mechanisms regulating SHORT-ROOT intercellular movement.
Signaling centers within developing organs regulate morphogenesis in both plants and animals. The putative transcription factor SHORT-ROOT (SHR) is an organizing signal regulating the division of specific stem cells in the Arabidopsis root. Comparison of gene transcription with protein localization indicates that SHR moves in a highly specific manner from the cells of the stele in which it is synthesized outward. Here, we provide evidence that SHR intercellular trafficking is both regulated and targeted. First, we show that subcellular localization of SHR in the stele is intrinsic to the SHR protein. Next, we show that SHR must be present in the cytoplasm to move, providing evidence that SHR movement is regulated. Finally, we describe an informative new shr allele, in which the protein is present in the cytoplasm yet does not move. Thus, in contrast to proteins that move by a process resembling diffusion, a cytoplasmic pool of SHR is not sufficient for movement.
Gallagher
Kimberly L
KL
Department of Biology, Duke University, Durham, NC 27708, USA.
Paquette
Alice J
AJ
Nakajima
Keiji
K
Benfey
Philip N
PN
D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D003593:Cytoplasm / Q000378:metabolism; D017931:DNA Primers; D049452:Green Fluorescent Proteins; D018613:Microscopy, Confocal; D008954:Models, Biological; D018517:Plant Roots / Q000378:metabolism*; D017354:Point Mutation / Q000235:genetics; D021381:Protein Transport / Q000502:physiology; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D014170:Transformation, Genetic
D029681:Arabidopsis Proteins; D017931:DNA Primers; C100978:SCR protein, Arabidopsis; C410510:SHORT ROOT protein, Arabidopsis; D014157:Transcription Factors; D049452:Green Fluorescent Proteins