RTM3, which controls long-distance movement of potyviruses, is a member of a new plant gene family encoding a meprin and TRAF homology domain-containing protein.
Restriction of long-distance movement of several potyviruses in Arabidopsis (Arabidopsis thaliana) is controlled by at least three dominant restricted TEV movement (RTM) genes, named RTM1, RTM2, and RTM3. RTM1 encodes a protein belonging to the jacalin family, and RTM2 encodes a protein that has similarities to small heat shock proteins. In this article, we describe the positional cloning of RTM3, which encodes a protein belonging to an undescribed protein family of 29 members that has a meprin and TRAF homology (MATH) domain in its amino-terminal region and a coiled-coil domain at its carboxy-terminal end. Involvement in the RTM resistance system is the first biological function experimentally identified for a member of this new gene family in plants. Our analyses showed that the coiled-coil domain is not only highly conserved between RTM3-homologous MATH-containing proteins but also in proteins lacking a MATH domain. The cluster organization of the RTM3 homologs in the Arabidopsis genome suggests the role of duplication events in shaping the evolutionary history of this gene family, including the possibility of deletion or duplication of one or the other domain. Protein-protein interaction experiments revealed RTM3 self-interaction as well as an RTM1-RTM3 interaction. However, no interaction has been detected involving RTM2 or the potyviral coat protein previously shown to be the determinant necessary to overcome the RTM resistance. Taken together, these observations strongly suggest the RTM proteins might form a multiprotein complex in the resistance mechanism to block the long-distance movement of potyviruses.
Cosson
Patrick
P
UMR Génomique, Diversité et Pouvoir Pathogène, INRA-Université Bordeaux 2, Institut de Biologie Végétale Moléculaire, Villenave d'Ornon, France.
Sofer
Luc
L
Le
Quang Hien
QH
Léger
Valérie
V
Schurdi-Levraud
Valérie
V
Whitham
Steven A
SA
Yamamoto
Miki L
ML
Gopalan
Suresh
S
Le Gall
Olivier
O
Candresse
Thierry
T
Carrington
James C
JC
Revers
Frédéric
F
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000821:virology; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D001692:Biological Transport; D036022:Capsid Proteins / Q000378:metabolism; D017343:Genes, Plant / Q000235:genetics*; D005838:Genotype; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics*; D037121:Plant Lectins / Q000378:metabolism; D017800:Potyvirus / Q000378:metabolism*; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D008625:Tiopronin / Q000378:metabolism*; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins / Q000737:chemistry*; D020798:Two-Hybrid System Techniques
D029681:Arabidopsis Proteins; D036022:Capsid Proteins; D037121:Plant Lectins; C403528:RTM1 protein, Arabidopsis; C554275:RTM3 protein, Arabidopsis; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins; D008625:Tiopronin