Molecular characterization and concerted evolution of two genes encoding RING-C2 type proteins in rice.
RING (Really Interesting New Gene) finger proteins are believed to play a critical role in mediating the transfer of ubiquitin to heterogeneous substrate(s). While the two canonical types, RING-H2 and RING-HC, have been well-characterized, the molecular functions of the modified types, particularly the RING-C2 types, remain elusive. We isolated two rice genes harboring the RING-C2 domain on the distal parts of rice chromosomes 11 and 12, termed OsRINGC2-1 and OsRINGC2-2, respectively. A comparison of sequence divergences between 10 duplicate pairs on the distal parts of rice chromosomes 11 and 12 and randomly selected duplicate pairs suggested that OsRINGC2-1 and OsRINGC2-2 have evolved in concert via gene conversion. An in vitro ubiquitination assay revealed that both proteins possess E3 ligase activity, suggesting that the innate functions of these RING domains have not been affected by their modifications during evolution. Subcellular localizations were strikingly different; OsRINGC2-1 was found only in the cytoplasm with many punctate complexes, whereas OsRINGC2-2 was observed in both the nucleus and cytoplasm. The expression patterns of both genes showed striking differences in response to salt stress, whereas plants heterogeneous for both genes mediated salt tolerance in Arabidopsis, supporting the notion of concerted evolution. These results shed light on the molecular functions of OsRINGC2-1 and OsRINGC2-2 and provide insight into their molecular evolution.
Plant Genomics Lab, Department of Applied Plant Sciences, Kangwon National University, Chuncheon 200‐713, Korea.
Chang Gyo
CG
Jung
Sung Don
SD
Lim
Sun-Goo
SG
Hwang
Cheol Seong
CS
Jang
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D032461:Chromosomes, Plant / Q000502:physiology; D003593:Cytoplasm / Q000235:genetics / Q000378:metabolism; D019143:Evolution, Molecular; D017343:Genes, Plant / Q000502:physiology; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D044767:Ubiquitin-Protein Ligases / Q000235:genetics* / Q000378:metabolism
D002352:Carrier Proteins; D010940:Plant Proteins; D044767:Ubiquitin-Protein Ligases