Abstract
A rapidly labelled rRNA precursor can be detected in callus cells of Petroselinum sativum grown on a liquid synthetic medium. Its molecular weight has been calculated to be 2.3×106. This value agrees with that of the rRNA precursor from other plant material. In order to follow the synthesis and processing of rRNA in time and to correlate single steps in this process with cell organelles it was necessary to obtain pure fractions of nuclei and ribosomes. The isolation method for nuclei is given in detail. The nucleic acids are separated on polyacrylamide gels of low acrylamide concentration. Pulse-chase experiments show that the rRNA precursor is split into two fragments within the nucleus: an 18S and a 25S component. The 18S RNA leaves the nucleus rapidly. It is already found quantitatively in the ribosomal fraction after 30–60 min chase. At that time the 25S RNA is still within the nucleus; it appears much later in the ribosomes. Since the increase in ribosomal label occurs simultaneously with the decrease in nuclear label, it is concluded that there is no degradation of 18S RNA within the nucleus. Apparently there are two distinct transport mechanisms with different kinetics for the two RNA components.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: 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.