Increased rDNA synthesis in germinated conidia of Neurospora crassa is caused by RNA primer molecules found in its culture medium
Purine rich small primer RNA molecules (10-15 nucleotides) were isolated from growth medium of germinated (3 hr sprout) conidia of N. crassa. These RNA-primer molecules strongly stimulated in vitro DNA synthesis in N. crassa 74A wild type, as well as in DNAs from mice spleen and lung, and quail testis. These increases of in vitro DNA synthesis was dependent on the concentration of these RNA primer molecules. In contrast, such molecules were not found in 1 or 10 hour sprouts, nor in the culture medium of mycelia (24 hr). These RNA-primer molecules could be hydrolyzed by T1 RNAse but not by pancreatic RNase. Dutta et al. reported increased (250) copies of rRNA genes in germinated conidia (3 hr sprouts) compared to 100 copies of rRNA genes in mycelial cells grown for 24 hours. These observations suggest excessive transcription of rDNAs in the germinated conidial cells which undergo cleavages by nucleates after 3-4 hours of cell growth. Some degradation products were excreted into the culture medium and acted as RNA-primers.
- Research Organization:
- Howard Univ., Washington, DC
- OSTI ID:
- 6258708
- Journal Information:
- Genetics; (United States), Vol. 107:3
- Country of Publication:
- United States
- Language:
- English
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NEUROSPORA
DNA REPLICATION
BIRDS
CONIDIA
CULTURE MEDIA
GENES
LUNGS
MICE
RNA
RNA-ASE
SPLEEN
TESTES
TRANSCRIPTION
ANIMALS
BODY
ENZYMES
ESTERASES
FUNGI
GONADS
HYDROLASES
MALE GENITALS
MAMMALS
NUCLEIC ACID REPLICATION
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PHOSPHODIESTERASES
PLANTS
RESPIRATORY SYSTEM
RODENTS
SPORES
VERTEBRATES
550400* - Genetics