Profiles of nuclear and mitochondrial encoded mRNAs in developing and quiescent embryos of Artemia franciscana
| Autor: | Steven C. Hand, Douglas L. Crawford, Iris Hardewig, Anchordoguy Thomas Joseph |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Protein subunit
Intracellular pH Clinical Biochemistry Molecular Sequence Data Electron Transport Complex IV Oxygen Consumption medicine Protein biosynthesis Cytochrome c oxidase Animals RNA Messenger Molecular Biology Actin Acidosis Cell Nucleus Messenger RNA biology Cell Biology General Medicine Metabolism Blotting Northern Actins Cell biology Mitochondria Biochemistry biology.protein medicine.symptom Artemia DNA Probes |
| Zdroj: | Molecular and cellular biochemistry. 158(2) |
| ISSN: | 0300-8177 |
| Popis: | Embryos of the brine shrimp Artemia franciscana are able to withstand long bouts of environmental anoxia by entering a quiescent state during which metabolism is greatly depressed. Recent evidence supports a global arrest of protein synthesis during quiescence. In this study we measured the amounts of mRNA for a mitochondrial-encoded subunit of cytochrome c oxidase (COX I) and for nuclear-encoded actin during aerobic development, anaerobiosis, and aerobic acidosis (artificial quiescence imposed by intracellular acidification under aerobic conditions). The levels of both COX I and actin transcripts increased significantly during aerobic development. COX I mRNA levels were tightly correlated with previous measures of COX catalytic activity, which suggests that COX synthesis could be regulated by message concentration during aerobic development. The ontogenetic increase for these mRNAs was blocked by anoxia and aerobic acidosis. Importantly, the levels of COX I and actin mRNA did not decline appreciably during the 6 h bouts of quiescence, even though protein synthesis is acutely arrested by these same treatments. Thus, the constancy of mRNA levels during quiescence indicate that reduced protein synthesis is not caused by message limitation, but rather, is likely controlled at the translational level. One advantage of this regulatory mechanism is the conservation of mRNA molecules during quiescence, which would potentially favor a quick resumption of translation as soon as oxygen is returned to the embryos. Finally, because anoxia and aerobic acidosis are both characterized by acidic intracellular pH, the reduction in pH may serve, directly or indirectly, as one signal regulating levels of mRNA in this embryo during quiescence. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full text from SpringerLink