Circ Res

RationaleDiscerning cardiac myocyte cell cycle behavior is challenging owing to commingled cell types with higher proliferative activity.ObjectiveTo investigate cardiac myocyte cell cycle activity in development and the early postnatal period.Methods and ResultsTo facilitate studies of cell type\u2013specific proliferation, we have generated tissue-specific cell cycle indicator BAC transgenic mouse lines. Experiments using embryonic fibroblasts from CyclinA2-LacZ-floxed-EGFP, or CyclinA2-EGFP mice, demonstrated that CyclinA2-\u3b2gal and CyclinA2-EGFP were expressed from mid-G1 to mid-M phase. Using Troponin T-Cre;CyclinA2-LacZ-EGFP mice, we examined cardiac myocyte cell cycle activity during embryogenesis and in the early postnatal period. Our data demonstrated that right ventricular cardiac myocytes exhibited reduced cell cycle activity relative to left ventricular cardiac myocytes in the immediate perinatal period. Additionally, in contrast to a recent report, we could find no evidence to support a burst of cardiac myocyte cell cycle activity at postnatal day 15.ConclusionsOur data highlight advantages of a cardiac myocyte\u2013specific cell cycle reporter for studies of cardiac myocyte cell cycle regulation.UM1 HL128773/HL/NHLBI NIH HHS/United StatesDP1HL117649/DP/NCCDPHP CDC HHS/United StatesP30 NS047101/NS/NINDS NIH HHS/United StatesDP1 OD006428/OD/NIH HHS/United StatesR01 HL123747/HL/NHLBI NIH HHS/United StatesR01HL123747/HL/NHLBI NIH HHS/United StatesDP1 HL117649/HL/NHLBI NIH HHS/United States2017-07-28T00:00:00Z26472817PMC5533092vault:2381