De novo dNTP production is essential for normal postnatal murine heart development

• Published in: The Journal of biological chemistry Vol. 294; no. 44; pp. 15889 - 15897
• Main Authors: Tran, Phong, Wanrooij, Paulina H., Lorenzon, Paolo, Sharma, Sushma, Thelander, Lars, Nilsson, Anna Karin, Olofsson, Anna-Karin, Medini, Paolo, von Hofsten, Jonas, Stål, Per, Chabes, Andrei
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.11.2019; American Society for Biochemistry and Molecular Biology
• Subjects: Animals; cardiac function; cardiac muscle; cardiomyocyte; deoxyribonucleoside kinases; Deoxyribonucleotides - biosynthesis; desmin; DNA Replication; dNTP metabolism; dNTP salvage; dystrophin; Editors' Picks; Heart - growth & development; Heart - physiology; heart development; laminin; Mice; Mice, Inbred C57BL; Muscle Proteins - genetics; Muscle Proteins - metabolism; Myocytes, Cardiac - metabolism; nucleoside/nucleotide biosynthesis; nucleoside/nucleotide metabolism; ribonucleotide reductase; ribonucleotide reductase (RNR); Ribonucleotide Reductases - genetics; Ribonucleotide Reductases - metabolism; heart development; nucleoside/nucleotide metabolism; deoxyribonucleoside kinases; nucleoside/nucleotide biosynthesis; desmin; ribonucleotide reductase (RNR); dystrophin; dNTP metabolism; cardiomyocyte; cardiac function; laminin; cardiac muscle; dNTP salvage
• ISSN: 0021-9258; 1083-351X; 1083-351X
• DOI: 10.1074/jbc.RA119.009492

The building blocks of DNA, dNTPs, can be produced de novo or can be salvaged from deoxyribonucleosides. However, to what extent the absence of de novo dNTP production can be compensated for by the salvage pathway is unknown. Here, we eliminated de novo dNTP synthesis in the mouse heart and skeletal muscle by inactivating ribonucleotide reductase (RNR), a key enzyme for the de novo production of dNTPs, at embryonic day 13. All other tissues had normal de novo dNTP synthesis and theoretically could supply heart and skeletal muscle with deoxyribonucleosides needed for dNTP production by salvage. We observed that the dNTP and NTP pools in WT postnatal hearts are unexpectedly asymmetric, with unusually high dGTP and GTP levels compared with those in whole mouse embryos or murine cell cultures. We found that RNR inactivation in heart led to strongly decreased dGTP and increased dCTP, dTTP, and dATP pools; aberrant DNA replication; defective expression of muscle-specific proteins; progressive heart abnormalities; disturbance of the cardiac conduction system; and lethality between the second and fourth weeks after birth. We conclude that dNTP salvage cannot substitute for de novo dNTP synthesis in the heart and that cardiomyocytes and myocytes initiate DNA replication despite an inadequate dNTP supply. We discuss the possible reasons for the observed asymmetry in dNTP and NTP pools in WT hearts.