title: Early initiation of DNA synthesis in G1 phase HeLa cells following fusion with red cell ghosts loaded with S-phase cell extracts.
abstract: A modification of polyethylene glycol-mediated cell fusion procedure has been described and standardized for red blood cell mediated microinjection of proteins into cells in suspension. Using this procedure, proteins are routinely introduced into 50% of the target cells. We have applied this microinjection procedure to introduce cytoplasmic extracts obtained from S-phase HeLa cells into HeLa cells synchronized in G1. This experiment resulted in an accelerated entry of the G1 cells into S phase as measured by the incorporation of [3H]thymidine. This technique may provide a means to identify and characterize the S-phase factors responsible for the induction of DNA synthesis.
mesh_terms: D002453:Cell Cycle; D002459:Cell Fusion; D004261:DNA Replication; D004910:Erythrocyte Membrane / Q000648:ultrastructure*; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells / Q000166:cytology / Q000378:metabolism; D006801:Humans; D007399:Interphase; D007700:Kinetics; D008938:Mitosis; D010047:Ovalbumin / Q000032:analysis; D014020:Tissue Extracts / Q000494:pharmacology
chemical_list: D014020:Tissue Extracts; D010047:Ovalbumin