Studies of Xenopus laevis mitochondrial DNA: D-loop mapping and characterization of DNA-binding proteins
In X. laevis oocytes, mitochondrial DNA accumulates to 10/sup 5/ times the somatic cell complement, and is characterized by a high frequency of a triple-stranded displacement hoop structure at the origin of replication. To map the termini of the single strands, it was necessary to correct the nucleotide sequence of the D-loop region. The revised sequence of 2458 nucleotides contains 54 discrepancies in comparison to a previously published sequence. Radiolabeling of the nascent strands of the D-loop structure either at the 5' end or at the 3' end identifies a major species with a length of 1670 nucleotides. Cleavage of the 5' labeled strands reveals two families of ends located near several matches to an element, designated CSB-1, that is conserved in this location in several vertebrate genomes. Cleavage of 3' labeled strands produced one fragment. The unique 3' end maps to about 15 nucleotides preceding the tRNA/sup Pro/ gene. A search for proteins which may bind to mtDNA in this region to regulate nucleic acid synthesis has identified three activities in lysates of X. laevis mitochondria. The DNA-binding proteins were assayed by monitoring their ability to retard the migration of labeled double- or single-stranded DNA fragments in polyacrylamide gels. The DNA binding preference was determined by competition with an excess of either ds- or ssDNA.
- Research Organization:
- State Univ. of New York, Stony Brook (USA)
- OSTI ID:
- 6292023
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
DNA
MOLECULAR STRUCTURE
FROGS
DNA SEQUENCING
PROTEINS
CHEMICAL COMPOSITION
AMINO ACID SEQUENCE
BIOCHEMICAL REACTION KINETICS
ELECTROPHORESIS
LABELLED COMPOUNDS
MITOCHONDRIA
RADIOISOTOPES
TRACER TECHNIQUES
AMPHIBIANS
ANIMALS
AQUATIC ORGANISMS
CELL CONSTITUENTS
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANOIDS
REACTION KINETICS
STRUCTURAL CHEMICAL ANALYSIS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques