Acquisition of multiple nuclei and the activity of DNA polymerase alpha and reinitiation of DNA replication in terminally differentiated adult cardiac muscle cells in culture

Journal Article · Sat Oct 01 04:00:00 EDT 1983 · Dev. Biol.; (United States)

DOI:https://doi.org/10.1016/0012-1606(83)90283-X· OSTI ID:6983132

Claycomb, W C; Bradshaw, Jr, H D

Terminally differentiated ventricular cardiac muscle cells isolated from the adult rat and maintained in cell culture have been observed to acquire multiple nuclei. In one cultured myocyte as many as 10 nuclei have been counted. Apparently, these multiple nuclei are formed by DNA replication followed by karyokinesis; the cells must then fail to complete mitosis and divide. To investigate whether DNA synthesis was occurring, the cells were cultured in the presence of (3H)thymidine and then processed for autoradiography. Mononucleated, binucleated, and multinucleated cells incorporate (3H)thymidine into DNA as evidenced by the high concentration of silver grains over their nuclei. Peak periods of incorporation were observed to occur at 10- to 12-day intervals; at 11, 23, and 33 days after initially placing the cells in culture. When the cells were maintained in the presence of (3H)thymidine continuously from Day 7 to Day 17 of culture, 23% of the cells became labeled. If the cells were cultured continuously for 30 days in the presence of (3H)thymidine, from Day 10 to Day 40, 56% of the cells were labeled. Isopycnic gradient analysis indicates that this thymidine incorporation was into DNA that was being replicated semiconservatively; these experiments did not eliminate the possibility, however, that this incorporation was due to amplification of specific genes, such as those coding for the contractile proteins. The activity of DNA polymerase alpha also returns to these cells. These studies demonstrate that the terminally differentiated mammalian ventricular cardiac muscle cell, previously thought to have permanently lost the capacity to replicate DNA during early development, is able to reinitiate semiconservative DNA replication when grown in culture.

• OSTI ID: 6983132
• Journal Information: Dev. Biol.; (United States), Journal Name: Dev. Biol.; (United States) Vol. 99:2; ISSN DEBIA
• Country of Publication: United States
• Language: English

Related Subjects

550301* -- Cytology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
ANIMALS
AUTORADIOGRAPHY
AZINES
BODY
CARDIOVASCULAR SYSTEM
CELL CULTURES
DNA
DNA POLYMERASES
DNA REPLICATION
ENZYME ACTIVITY
ENZYMES
HEART
HETEROCYCLIC COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MUSCLES
NUCLEIC ACID REPLICATION
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
NUCLEOTIDYLTRANSFERASES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PHOSPHORUS-GROUP TRANSFERASES
POLYMERASES
PYRIMIDINES
RATS
RIBOSIDES
RODENTS
THYMIDINE
TRACER TECHNIQUES
TRANSFERASES
TRITIUM COMPOUNDS
VERTEBRATES