5'-Ends of Ribosomal and Ribosomal Precursor RNAs from Xenopus laevis
نویسندگان
چکیده
منابع مشابه
More ribosomal spacer sequences from Xenopus laevis.
The base sequence analysis of a Xenopus laevis ribosomal DNA repeat (7) has been extended to cover almost the entire non-transcribed and external transcribed spacer. A compilation of these sequences is presented. All the repetitive and non-repetitive sequence elements of the spacer are identified and their evolution discussed. Comparison of the X.laevis and S.cerevisiae (25,26) ribosomal DNAs s...
متن کاملXenopus laevis ribosomal protein S1a cDNA sequence.
In Xenopus laevis the coordinated synthesis of the over 80 ribosomal proteins (r-proteins) is attained by both post-transcriptional and translational level regulation (1, 2). Also several r-protein genes analyzed present structural similarities probably involved in the common regulatory mechanisms. Our understanding, however, of the structure and expression of these genes is based on the analys...
متن کاملCompact structure of ribosomal chromatin in Xenopus laevis.
Micrococcal nuclease digestion was used as a tool to study the organization of the ribosomal chromatin in liver, blood and embryo cells of X. laevis. It was found that in liver and blood cells, ribosomal DNA is efficiently protected from nuclease attack in comparison to bulk chromatin. Although ribosomal chromatin is fragmented in a typical nucleosomal pattern, a considerable portion of ribosom...
متن کاملTranscription in cloned spacers of Xenopus laevis ribosomal DNA.
Rare individuals of Xenopus laevis exhibit frequent initiation of transcription in the spacers of oocyte ribosomal DNA (rDNA). Using electron microscopy we have characterized spacer transcription in such an individual and have confirmed that the sites of transcription initiation correspond to the imperfectly duplicated promoters ("Bam islands") present in the X. laevis rDNA spacer. We have clon...
متن کاملFunctional difference between the sites of ribosomal 40S precursor 3' end formation in Xenopus laevis and Xenopus borealis.
In the ribosomal genes of X. laevis, the sequence GACTTGCNC is found about 60bp upstream of the gene promoter (T3) and is necessary and sufficient to cause termination of RNA polymerase I transcription. At the 3' end of the 40S precursor coding region (T2) a sequence differing by one nucleotide, GACTTGCNG, directs RNA 3' end formation but allows polymerase to transcribe on into the intergenic s...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: European Journal of Biochemistry
سال: 1974
ISSN: 0014-2956,1432-1033
DOI: 10.1111/j.1432-1033.1974.tb03384.x