title: Replication pattern of human repeated DNA sequences.
abstract: Either aphidicolin- or thymidine-synchronized human HL-60 cells were used to study the replication pattern of a family of human repetitive DNA sequences, the Eco RI 340 bp family (alpha RI-DNA), and of the ladders of fragments generated in total human DNA after digestion with XbaI and HaeIII (alpha satellite sequences). DNAs replicated in early, middle-early, middle-late and late S periods were labelled with BUdR or with [3H]thymidine. The efficiency of the cell synchronization procedure was confirmed by the transition from a high-GC to a high-AT average base composition of the DNA synthesized going from early to late S periods. By hybridizing EcoRI 340 bp repetitive fragments to BUdR-DNAs it was found that this family of sequences is replicated throughout the entire S period. Comparing fluorograph densitometric scans of [3H]DNAs to the scans of ethidium bromide patterns of total HL-60 DNA digested with XbaI and HaeIII, it was observed that DNA synthesized in different S periods is characterized by approximately the same ladder of fragments, while the intensity of each band may vary through the S phase; in particular, the XbaI 2.4 kb fragment becomes undetectable in late S.
mesh_terms: D001483:Base Sequence; D002460:Cell Line; D002499:Centrifugation, Density Gradient; D004247:DNA / Q000032:analysis*; D004262:DNA Restriction Enzymes / Q000378:metabolism; D015246:Deoxyribonuclease EcoRI; D015252:Deoxyribonucleases, Type II Site-Specific; D006801:Humans; D007951:Leukemia, Myeloid / Q000235:genetics; D009690:Nucleic Acid Conformation; D009693:Nucleic Acid Hybridization; D012091:Repetitive Sequences, Nucleic Acid
chemical_list: D004247:DNA; D004262:DNA Restriction Enzymes; D015246:Deoxyribonuclease EcoRI; C025580:endodeoxyribonuclease XBAI; D015252:Deoxyribonucleases, Type II Site-Specific; C024403:GGCC-specific type II deoxyribonucleases