title: Satellite DNA from Xenopus laevis: comparative analysis of 745 and 1037 base pair Hind III tandem repeats.
abstract: Highly repetitive Hind III restriction fragments of 0.72-0.76 KBP from total Xenopus laevis genomic DNA are organized in a tandem like arrangement. Cloning of these fragments in pBR 322 with subsequent restriction site mapping and nucleotide sequence analysis of some selected clones showed two different types of sequences. 25-30% of material represent the oocyte specific 5 S DNA repeat units, 70-75% are similar to the recently described repeat elements of satellite 1 DNA. Hybridization of a genomic DNA library to such a 745 BP monomeric repeat unit and investigation of some clones with positive autoradiographic signals revealed structural heterogeneities of repeat elements, in that the 745 BP sequence cross-hybridized with 1037 BP Hind III repeat units. Nucleotide sequence analysis demonstrated that the two types of sequences show a homology of 84.3% and that the 1037 BP sequence additionally contains duplicated elements of the 745 BP sequence as well as apparently unrelated DNA sequences.
mesh_terms: D000818:Animals; D001482:Base Composition; D001483:Base Sequence; D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes; D004276:DNA, Satellite / Q000235:genetics*; D015247:Deoxyribonuclease HindIII; D009693:Nucleic Acid Hybridization; D014176:Protein Biosynthesis; D012091:Repetitive Sequences, Nucleic Acid; D014981:Xenopus
chemical_list: D004276:DNA, Satellite; D004262:DNA Restriction Enzymes; D015247:Deoxyribonuclease HindIII