Mutation of the gene for the second-largest subunit of RNA polymerase I prolongs the period length of the circadian conidiation rhythm in Neurospora crassa.
The period length of the circadian conidiation rhythm was examined in a mutant strain of Neurospora crassa, un-18, that is temperature sensitive for mycelial growth. The un-18 mutant showed a temperature-sensitive phenotype with respect to both mycelial growth and the period length of the conidiation rhythm. Below 22 degrees C, the un-18 mutation did not affect the period length, but at temperatures between 22 degrees C and 32 degrees C, the period length of the un-18 mutant was approximately 2 h longer than that of the wild-type strain. The un-18+ gene was cloned and was found to encode the second-largest subunit of RNA polymerase I, which is involved in the synthesis of rRNA. These results indicate that a defect in ribosome synthesis, which must result in a lower rate of protein synthesis, lengthens the period of the circadian conidiation rhythm in Neurospora.
Onai
K
K
Department of Biology, Faculty of Science, Okayama University, Japan.
Katagiri
S
S
Akiyama
M
M
Nakashima
H
H
D000595:Amino Acid Sequence; D001483:Base Sequence; D002940:Circadian Rhythm / Q000235:genetics*; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D009154:Mutation; D009492:Neurospora crassa / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development; D016133:Polymerase Chain Reaction; D011487:Protein Conformation; D012318:RNA Polymerase I / Q000737:chemistry / Q000235:genetics*; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D013696:Temperature; D014170:Transformation, Genetic
D017931:DNA Primers; D004271:DNA, Fungal; D012318:RNA Polymerase I