Abstract
The pathway of ribosomal RNA biogenesis in Dictyostelium discoideum has been defined through identification, isolation, and characterization of the rapidly labeled nuclear RNAs which are intermediates in the process. Comparison of the methylation patterns, base compositions, two-dimensional oligonucleotide maps, and hybridization properties of these intermediate RNAs with those of mature rRNAs has established clearly the precursor-product sequence relationships supporting the following scheme for rRNA production and processing: (formula: see text) The relationship of the 37 S RNA of Dictyostelium to primary rRNA transcripts of prokaryotes and other eukaryotes is discussed.
Highlights
The pathway of ribosomal RNA biogenesis in Dirtyostelium discoideum has been defined through identification, isolation, and characterization of the rapidly labeled nuclear RNAs which are intermediates in the process
We have characterized three discrete, rapidly labeled RNA species, all extensively methylated, from the nuclei of starved and developing Dictyostelium discoideum. These RNAs correspond in mobility and methylation properties to very transient radioactive species observed by Iwabuchi et al [13] in sucrose gradient profiles of whole cell RNA from vegetative NC-4 Dictyostelium (NC-4 is parent to the axenic strain we have used)
The one possible exception is a 30 S RNA intermediate, observed as a shoulder in Iwabuchi’s gradients of vegetative RNA, which we do not detect in high resolution agarose gel profiles of nuclear RNA from starved or developing cells
Summary
“Hlmethionine had a specific activity of 11.5 Ci/mmol. Sigma; after a bottle had been opened, it was used for only 2 weeks before being discarded. The two phases separated by the centrifugation were each re-extracted separately: the upper aqueous phase plus interphase with 2 volumes of phenol:chloroform:isoamyl alcohol (50:48:2), and the lower organic phase with 2 ml of HMK buffer containing 0.2 M sodium acetate, pH 7.3. Both samples were agitated and centrifuged as above. The RNA pellets were dried, resuspended in gel sample solution, and fractionated further by electrophoresis on slab or cylindrical agarose gels by the procedure detailed above. 42” in a large volume of 50% formamideih x, SSC, and washed extensively in 5 x SSC
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
