Antisense RNA inhibition of the beta subunit of the Dictyostelium discoideum mitochondrial processing peptidase induces the expression of mitochondrial proteins.
We cloned and characterized a cDNA encoding the Dictyostelium discoideum beta subunit of mitochondrial processing peptidase (Ddbeta-MPP). Western blot analysis of the mitochondrial subfractions revealed that Ddbeta-MPP is located in the mitochondrial matrix and membrane, whereas Dd(alpha)-MPP, another subunit of DdMPP, is located only in the matrix. Although expression of Ddbeta-MPP mRNA is down-regulated during early development, the level of the Ddbeta-MPP protein is constant throughout the Dictyostelium life cycle. In a transformant expressing the antisense RNA of the beta-MPP gene, unexpectedly, the beta-MPP protein increased about 1.8-fold relative to the wild type, and its mRNA increased 4.5-fold. Expression of other mitochondrial proteins, alpha-MPP and Cox IV, was also induced. These results suggest that antisense RNA inhibition of the beta-MPP gene induces gene expression of mitochondrial proteins, presumably in a retrograde signaling manner. This is the pathway of the transfer of information from the mitochondria to the nucleus.
Nagayama
Koki
K
Science of Bioresources, United Graduate School of Agricultural Sciences, Iwate University, Morioka, Japan.
Itono
Shiori
S
Yoshida
Takashi
T
Ishiguro
Sei-ichi
S
Ochiai
Hiroshi
H
Ohmachi
Tetsuo
T
D000818:Animals; D004023:Dictyostelium / Q000201:enzymology*; D005786:Gene Expression Regulation; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors*; D024101:Mitochondrial Proteins / Q000235:genetics*; D021122:Protein Subunits; D016372:RNA, Antisense / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis; D000096122:Mitochondrial Processing Peptidase
D008666:Metalloendopeptidases; D024101:Mitochondrial Proteins; D021122:Protein Subunits; D016372:RNA, Antisense; D012333:RNA, Messenger; D000096122:Mitochondrial Processing Peptidase