The real factor for polypeptide elongation in Dictyostelium cells is EF-2B, not EF-2A.
Polypeptide elongation factor 2 (EF-2) plays an essential role in protein synthesis and is believed to be indispensable for cell proliferation. Recently, it has been demonstrated that there are two kinds of EF-2 (EF-2A and EF-2B with 76.6% of sequence identity at the amino acid level) in Dictyostelium discoideum. Although the knockout of EF-2A slightly impaired cytokinesis, EF-2A null cells exhibited almost normal protein synthesis and cell growth, suggesting that there is another molecule capable of compensating for EF-2 function. Since EF-2B is the most likely candidate, we examined its function using ef-2b knockdown cells prepared by the RNAi method. Our results strongly suggest that EF-2B is required for protein synthesis and cell proliferation, functioning as the real EF-2. Interestingly, the expressions of ef-2a and ef-2b mRNAs during development are reversely regulated, and the ef-2b expression is greatly augmented in ef-2a null cells.
Yoshino
Tomoko
T
Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aoba, Sendai 980-8578, Japan.
Maeda
Yasuo
Y
Amagai
Aiko
A
D000595:Amino Acid Sequence; D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D017124:Conserved Sequence; D004023:Dictyostelium / Q000737:chemistry / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D020652:Peptide Elongation Factor 2 / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism*; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics; D016415:Sequence Alignment
D020652:Peptide Elongation Factor 2; D010455:Peptides; D012333:RNA, Messenger