DNA sequences for typical ribosomal gene spacers from Xenopus laevis and Xenopus borealis
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چکیده
منابع مشابه
Transcription 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 کاملMore 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 کاملMultiple heterogeneities in the transcribed spacers of ribosomal DNA from Xenopus laevis.
Ribosomal DNA (rDNA) from Xenopus laevis contains several heterogeneities in all three transcribed spacers, as revealed by analysis of cloned and uncloned amplified rDNA from oocytes and cloned chromosomal rDNA from erythrocytes. Heterogeneities include single base changes and length variants of one to several nucleotides. Sites of variation are widely but non-uniformly distributed, some occurr...
متن کاملPaternal gene expression in developing hybrid embryos of Xenopus laevis and Xenopus borealis.
We have studied protein synthesis in the viable hybrid Xenopus laevis (female) X Xenopus borealis (male) using 2D gel electrophoresis. Fourteen borealis-specific proteins were studied. Two of these proteins appeared by the gastrula stage, five in the gastrula and the rest later. Where homologous laevis proteins were tentatively identified, androgenetic haploid hybrids were used to study whether...
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...
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ژورنال
عنوان ژورنال: Nucleic Acids Research
سال: 1987
ISSN: 0305-1048,1362-4962
DOI: 10.1093/nar/15.8.3623