Newt myotubes reenter the cell cycle by phosphorylation of the retinoblastoma protein

Tanaka, E. M., Gann, A. A., Gates, P. B., Brockes, J. P. (January 1997) Newt myotubes reenter the cell cycle by phosphorylation of the retinoblastoma protein. Journal of Cell Biology, 136 (1). pp. 155-65. ISSN 0021-9525 (Print)0021-9525

DOI: 10.1083/jcb.136.1.155


Withdrawal from the cell cycle is an essential aspect of vertebrate muscle differentiation and requires the retinoblastoma (Rb) protein that inhibits expression of genes needed for cell cycle entry. It was shown recently that cultured myotubes derived from the Rb-/- mouse reenter the cell cycle after serum stimulation (Schneider, J.W., W. Gu, L. Zhu, V. Mahdavi, and B. Nadal-Ginard. 1994. Science (Wash. DC). 264:1467-1471). In contrast with other vertebrates, adult urodele amphibians such as the newt can regenerate their limbs, a process involving cell cycle reentry and local reversal of differentiation. Here we show that myotubes formed in culture from newt limb cells are refractory to several growth factors, but they undergo S phase after serum stimulation and accumulate 4N nuclei. This response to serum is inhibited by contact with mononucleate cells. Despite the phenotypic parallel with Rb-/- mouse myotubes, Rb is expressed in the newt myotubes, and its phosphorylation via cyclin-dependent kinase 4/6 is required for cell cycle reentry. Thus, the postmitotic arrest of urodele myotubes, although intact in certain respects, can be undermined by a pathway that is inactive in other vertebrates. This may be important for the regenerative ability of these animals.

Item Type: Paper
Uncontrolled Keywords: Amino Acid Sequence Animals Blood Carrier Proteins/physiology Cell Count Cell Cycle/physiology Cells, Cultured Cyclin-Dependent Kinase 4 Cyclin-Dependent Kinase 6 Cyclin-Dependent Kinase Inhibitor p16 Cyclin-Dependent Kinases/antagonists & inhibitors/physiology DNA Replication Enzyme Inhibitors Growth Substances/pharmacology Molecular Sequence Data Muscle Fibers, Skeletal/cytology/*metabolism Phosphorylation Protein-Serine-Threonine Kinases/physiology *Proto-Oncogene Proteins Retinoblastoma Protein/*metabolism S Phase/drug effects/*physiology Salamandridae
Subjects: organs, tissues, organelles, cell types and functions > cell types and functions > cell functions > cell cycle
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > genes, structure and function > gene expression
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein expression > phosphorylation
CSHL Authors:
Communities: School of Biological Sciences > SBS Administration
Depositing User: Matt Covey
Date: 13 January 1997
Date Deposited: 23 Jun 2014 18:46
Last Modified: 09 Sep 2021 18:45
PMCID: PMC2132456
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