Molecular cloning, differential expression, and functional characterization of a family of class I ubiquitin-conjugating enzyme (E2) genes in cotton (Gossypium).
Two cDNAs and their corresponding genes (GhUBC1 and GhUBC2) encoding ubiquitin-conjugating enzymes (E2s) have been cloned and characterized from allotetraploid cotton Gossypium hirsutum ((AD)(1) genome). Three additional E2 genes (GaUBC1, GtUBC2, and GrUBC2) have also been identified from diploid cottons Gossypium arboreum (A(2) genome), Gossypium thurberi (D(1) genome), and Gossypium raimondii (D(5) genome), respectively. The derived amino acid sequences of the five closely related cotton E2s are 77-79% identical to yeast ScUBC4 and ScUBC5. The GhUBC1/2 gene family is composed of two members, and genomic origin analysis indicates that GhUBC1 and 2 are individually present in the A and D subgenomes of G. hirsutum. The transcript levels of GhUBC1/2 increased significantly in leaves and flowers at senescence, suggesting that GhUBC1/2 may play a role in the degradation of target proteins that function in the delay of the senescence program. Correlated with high auxin content and auxin-associated effects, GhUBC1/2 are also highly expressed in the youngest leaves, the apical part of lateral roots, and elongating fibers. Genetic complementation experiments revealed that GhUBC1 and 2 can substitute for the function of ScUBC4 and 5 required for the selective degradation of abnormal and short-lived proteins in a yeast ubc4ubc5 double mutant.
Zhang
Xiang-Dong
XD
Department of Biochemistry and Molecular Biology, Box 9650, Mississippi State University, Mississippi State, MS 39762, USA.
Jenkins
Johnie N
JN
Callahan
Franklin E
FE
Creech
Roy G
RG
Si
Yang
Y
McCarty
Jack C
JC
Saha
Sukumar
S
Ma
Din-Pow
DP
D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000096:biosynthesis / Q000737:chemistry; D003368:Gossypium / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008025:Ligases / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012333:RNA, Messenger / Q000032:analysis; D016415:Sequence Alignment; D013045:Species Specificity; D044763:Ubiquitin-Conjugating Enzymes; D015003:Yeasts / Q000235:genetics
D018076:DNA, Complementary; D012333:RNA, Messenger; D044763:Ubiquitin-Conjugating Enzymes; D008025:Ligases