Evidence for Transport of 75S RNA from a Discrete Chromosome Region via Nuclear Sap to Cytoplasm in Chironomus tentans

AUTOR(ES)

Daneholt, B.

RESUMO

Salivary glands of the dipteran Chironomus tentans were exposed to tritiated pyrimidines for different time periods either in vitro or in vivo. Nonribosomal, high molecular weight RNA molecules of very different sizes (15-100 S) were labeled on chromosomes I-III, while only one main species, 75S RNA, was recorded in Balbiani ring 2, a giant chromosome puff on chromosome IV. 75S RNA was present as a prominent fraction in nuclear sap, but not in cytoplasm, after 90 min of incubation in vitro. During the ensuing 90 min, 75S RNA also appeared in cytoplasm. After 1 week of labeling in vivo, radioactive 75S RNA accumulated heavily in cytoplasm. Absorbance measurements showed that 75S RNA constituted as much as 1.5% of the total salivary-gland RNA. The half-life of 75S RNA was estimated to exceed 35 hr.

Documentos Relacionados

• Evidence for a Posttranscriptional Role of a TFIIICα-like Protein in Chironomus tentans
• The complexity of 75S premessenger RNA in balbiani ring granules studied by a new RNA band retardation assay.
• Electron microscopic visualization of a discrete class of giant translation units in salivary gland cells of Chironomus tentans
• An Electron Microscope Study of DNA Molecules from CHIRONOMUS TENTANS and CHIRONOMUS THUMMI
• Evidence for a common ancestor sequence for the Balbiani ring 1 and Balbiani ring 2 genes in Chironomus tentans