Studies of Xenopus laevis mitochondrial DNA: D-loop mapping and characterization of DNA-binding proteins

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:6292023

Cairns, S S

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
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACID SEQUENCE
AMPHIBIANS
ANIMALS
AQUATIC ORGANISMS
BIOCHEMICAL REACTION KINETICS
CELL CONSTITUENTS
CHEMICAL COMPOSITION
DNA
DNA SEQUENCING
ELECTROPHORESIS
FROGS
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LABELLED COMPOUNDS
MITOCHONDRIA
MOLECULAR STRUCTURE
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANOIDS
PROTEINS
RADIOISOTOPES
REACTION KINETICS
STRUCTURAL CHEMICAL ANALYSIS
TRACER TECHNIQUES
VERTEBRATES