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Molecular characterization of an Arabidopsis thaliana cDNA encoding a small GTP‐binding protein, Rha1
Author(s) -
Anuntalabhochai S.,
Terryn N.,
Montagu M.,
Inzé D.
Publication year - 1991
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.1991.00167.x
Subject(s) - arabidopsis thaliana , complementary dna , arabidopsis , gtp' , biology , genetics , computational biology , gene , chemistry , biochemistry , enzyme , mutant
Summary We have isolated a cDNA encoding a small GTP‐binding protein from an Arabidopsis thaliana cDNA library using an oligonucleotide probe derived from the most conserved domain of the ras superfamily. The cDNA encodes a 21.8 kDa protein, designated Rha1, which shows high homology to members of the ras super‐family in the regions involved in GTP binding, GTPase activity, and membrane attachment. The amino acid sequence is 60% identical to the sequence of the mammalian RabS protein, a small GTP‐binding protein which is believed to be involved in endocytosis. Several regions, including the putative effector domain are completely conserved. This high percentage of amino acid identity suggests that the Rha1 protein is the functional plant counterpart of the Rab5 protein. When expressed in E. coli , the Rha1 protein was shown to bind GTP. The rha 1 gene is most highly expressed in root and callus tissue, weakly expressed in stems and inflorescences and virtually not expressed in leaves and seed pods. Genomic Southern analysis revealed that rha 1 is part of a small multigene family.