{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,10]],"date-time":"2026-10-10T07:00:43Z","timestamp":1791615643284,"version":"4.3.4"},"reference-count":27,"publisher":"The Company of Biologists","issue":"12","license":[{"start":{"date-parts":[[2021,2,11]],"date-time":"2021-02-11T00:00:00Z","timestamp":1613001600000},"content-version":"vor","delay-in-days":72,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["5R01HL131788"],"award-info":[{"award-number":["5R01HL131788"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["5R01HL133589"],"award-info":[{"award-number":["5R01HL133589"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["1S10 OD025038"],"award-info":[{"award-number":["1S10 OD025038"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100008980","name":"Medical College of Wisconsin","doi-asserted-by":"publisher","award":["FP00012308"],"award-info":[{"award-number":["FP00012308"]}],"id":[{"id":"10.13039\/100008980","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2020,12,1]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n               <jats:p>Regeneration of muscle in the damaged myocardium is a major objective of cardiovascular research, for which purpose many investigators utilize mice containing transgenes encoding Cre recombinase to recombine loxP-flanked target genes. An unfortunate side effect of the Cre-loxP model is the propensity of Cre recombinase to inflict off-target DNA damage, which has been documented in various eukaryotic cell types including cardiomyocytes (CMs). In the heart, reported effects of Cre recombinase include contractile dysfunction, fibrosis, cellular infiltration and induction of the DNA damage response (DDR). During experiments on adult mice containing a widely used Myh6-merCremer transgene, the protein product of which is activated by tamoxifen, we observed large, transient, off-target effects of merCremer, some of which have not previously been reported. On Day 3 after the first of three daily tamoxifen injections, immunofluorescent microscopy of heart sections revealed that the presence of merCremer protein in myonuclei was nearly uniform, thereafter diminishing to near extinction by Day 6; during this time, cardiac function was depressed as determined by echocardiography. On Day 5, peaks of apoptosis and expression of DDR-regulatory genes were observed, highlighted by &amp;gt;25-fold increased expression of Brca1. Concomitantly, the expression of genes encoding cyclin-A2, cyclin-B2 and cyclin-dependent kinase 1, which regulate the G2\/S cell-cycle transition, were dramatically increased (&amp;gt;50- to 100-fold). Importantly, immunofluorescent staining revealed that this was accompanied by peaks in Ki67, 5\u2032-bromodeoxyuridine and phosphohistone H3 labeling in non-CMs, as well as CMs. We further document that tamoxifen-induced activation of merCremer exacerbates cardiac dysfunction following myocardial infarction. These findings, when considered in the context of previous reports, indicate that the presence of merCremer in the nucleus induces DNA damage and unscheduled cell-cycle activation. Although these effects are transient, the inclusion of appropriate controls, coupled with an awareness of the defects caused by Cre recombinase, are required to avoid misinterpreting results when using Cre-loxP models for cardiac regeneration studies.<\/jats:p>\n               <jats:p>This article has an associated First Person interview with the first author of the paper.<\/jats:p>","DOI":"10.1242\/dmm.046375","type":"journal-article","created":{"date-parts":[[2020,10,8]],"date-time":"2020-10-08T21:05:55Z","timestamp":1602191155000},"source":"Crossref","is-referenced-by-count":25,"title":["<i>Myh6<\/i>-driven Cre recombinase activates the DNA damage response and the cell cycle in the myocardium in the absence of loxP sites"],"prefix":"10.1242","volume":"13","author":[{"given":"Xinrui","family":"Wang","sequence":"first","affiliation":[{"name":"Medical College of Wisconsin 1 Department of Pharmacology and \u2008 Toxicology , , Milwaukee, WI 53226, \u2008 USA"},{"name":"Medical College of Wisconsin 2 Cardiovascular Center , , Milwaukee, WI 53226, \u2008 USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Amelia","family":"Lauth","sequence":"additional","affiliation":[{"name":"Medical College of Wisconsin 2 Cardiovascular Center , , Milwaukee, WI 53226, \u2008 USA"},{"name":"Medical College of Wisconsin 3 Department of Cell Biology, Neurobiology and Anatomy , , Milwaukee, WI 53226, \u2008 USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tina C.","family":"Wan","sequence":"additional","affiliation":[{"name":"Medical College of Wisconsin 1 Department of Pharmacology and \u2008 Toxicology , , Milwaukee, WI 53226, \u2008 USA"},{"name":"Medical College of Wisconsin 2 Cardiovascular Center , , Milwaukee, WI 53226, \u2008 USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"John W.","family":"Lough","sequence":"additional","affiliation":[{"name":"Medical College of Wisconsin 2 Cardiovascular Center , , Milwaukee, WI 53226, \u2008 USA"},{"name":"Medical College of Wisconsin 3 Department of Cell Biology, Neurobiology and Anatomy , , Milwaukee, WI 53226, \u2008 USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8005-4599","authenticated-orcid":false,"given":"John A.","family":"Auchampach","sequence":"additional","affiliation":[{"name":"Medical College of Wisconsin 1 Department of Pharmacology and \u2008 Toxicology , , Milwaukee, WI 53226, \u2008 USA"},{"name":"Medical College of Wisconsin 2 Cardiovascular Center , , Milwaukee, WI 53226, \u2008 USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"237","published-online":{"date-parts":[[2020,12,18]]},"reference":[{"key":"2024061302355730400_DMM046375C1","doi-asserted-by":"publisher","first-page":"1459","DOI":"10.1242\/dmm.010447","article-title":"Moderate and high amounts of tamoxifen in alphaMHC-MerCreMer mice induce a DNA damage response, leading to heart failure and death","volume":"6","author":"Bersell","year":"2013","journal-title":"Dis. Model. Mech."},{"key":"2024061302355730400_DMM046375C2","doi-asserted-by":"publisher","first-page":"814","DOI":"10.1067\/S0894-7317(03)00399-7","article-title":"Validation of the myocardial performance index by echocardiography in mice: a noninvasive measure of left ventricular function","volume":"16","author":"Broberg","year":"2003","journal-title":"J. Am. Soc. Echocardiogr."},{"key":"2024061302355730400_DMM046375C3","doi-asserted-by":"publisher","first-page":"e92903","DOI":"10.1371\/journal.pone.0092903","article-title":"A systematic review of fetal genes as biomarkers of cardiac hypertrophy in rodent models of diabetes","volume":"9","author":"Cox","year":"2014","journal-title":"PLoS ONE"},{"key":"2024061302355730400_DMM046375C4","doi-asserted-by":"publisher","first-page":"e0164855","DOI":"10.1371\/journal.pone.0164855","article-title":"Depletion of Tip60 from in vivo cardiomyocytes increases myocyte density, followed by cardiac dysfunction, myocyte fallout and lethality","volume":"11","author":"Fisher","year":"2016","journal-title":"PLoS ONE"},{"key":"2024061302355730400_DMM046375C5","doi-asserted-by":"publisher","first-page":"19422","DOI":"10.1038\/s41598-019-55950-w","article-title":"Dystrophin and calcium current are decreased in cardiomyocytes expressing Cre enzyme driven by alphaMHC but not TNT promoter","volume":"9","author":"Gillet","year":"2019","journal-title":"Sci. Rep."},{"key":"2024061302355730400_DMM046375C6","doi-asserted-by":"publisher","first-page":"H253","DOI":"10.1152\/ajpheart.00786.2010","article-title":"Systolic dysfunction in cardiac-specific ligand-inducible MerCreMer transgenic mice","volume":"301","author":"Hall","year":"2011","journal-title":"Am. J. Physiol. Heart Circ. Physiol."},{"key":"2024061302355730400_DMM046375C7","doi-asserted-by":"publisher","first-page":"H1671","DOI":"10.1152\/ajpheart.01155.2009","article-title":"Cre-loxP DNA recombination is possible with only minimal unspecific transcriptional changes and without cardiomyopathy in Tg(alphaMHC-MerCreMer) mice","volume":"299","author":"Hougen","year":"2010","journal-title":"Am. J. Physiol. Heart Circ. Physiol."},{"key":"2024061302355730400_DMM046375C8","doi-asserted-by":"publisher","first-page":"462","DOI":"10.4161\/cc.27271","article-title":"Cre recombinase induces DNA damage and tetraploidy in the absence of loxP sites","volume":"13","author":"Janbandhu","year":"2014","journal-title":"Cell Cycle"},{"key":"2024061302355730400_DMM046375C9","doi-asserted-by":"publisher","first-page":"152","DOI":"10.1002\/dvg.20720","article-title":"Unsuspected effects of a lung-specific Cre deleter mouse line","volume":"49","author":"Jeannotte","year":"2011","journal-title":"Genesis"},{"key":"2024061302355730400_DMM046375C10","doi-asserted-by":"publisher","first-page":"e128722","DOI":"10.1172\/jci.insight.128722","article-title":"Cell-specific ablation of Hsp47 defines the collagen-producing cells in the injured heart","volume":"4","author":"Khalil","year":"2019","journal-title":"JCI Insight"},{"key":"2024061302355730400_DMM046375C11","doi-asserted-by":"publisher","first-page":"12","DOI":"10.1161\/CIRCRESAHA.109.198416","article-title":"Avoidance of transient cardiomyopathy in cardiomyocyte-targeted tamoxifen-induced MerCreMer gene deletion models","volume":"105","author":"Koitabashi","year":"2009","journal-title":"Circ. Res."},{"key":"2024061302355730400_DMM046375C12","doi-asserted-by":"publisher","first-page":"420","DOI":"10.1016\/j.stem.2011.08.013","article-title":"Oncostatin M is a major mediator of cardiomyocyte dedifferentiation and remodeling","volume":"9","author":"Kubin","year":"2011","journal-title":"Cell Stem Cell"},{"key":"2024061302355730400_DMM046375C13","doi-asserted-by":"publisher","first-page":"260","DOI":"10.1038\/nature24045","article-title":"Hippo pathway deficiency reverses systolic heart failure after infarction","volume":"550","author":"Leach","year":"2017","journal-title":"Nature"},{"key":"2024061302355730400_DMM046375C14","doi-asserted-by":"publisher","first-page":"1470","DOI":"10.1242\/dmm.010470","article-title":"Cardiac fibrosis in mice expressing an inducible myocardial-specific Cre driver","volume":"6","author":"Lexow","year":"2013","journal-title":"Dis. Model. Mech."},{"key":"2024061302355730400_DMM046375C15","doi-asserted-by":"publisher","first-page":"9209","DOI":"10.1073\/pnas.161269798","article-title":"Growth inhibition and DNA damage induced by Cre recombinase in mammalian cells","volume":"98","author":"Loonstra","year":"2001","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"2024061302355730400_DMM046375C16","doi-asserted-by":"publisher","first-page":"19","DOI":"10.1016\/S0002-9149(99)00599-8","article-title":"Serial changes and prognostic implications of a Doppler-derived index of combined left ventricular systolic and diastolic myocardial performance in acute myocardial infarction","volume":"85","author":"Poulsen","year":"2000","journal-title":"Am. J. Cardiol."},{"key":"2024061302355730400_DMM046375C17","doi-asserted-by":"publisher","first-page":"54","DOI":"10.1016\/j.yjmcc.2015.06.019","article-title":"Prolonged Cre expression driven by the \u03b1-myosin heavy chain promoter can be cardiotoxic","volume":"86","author":"Pugach","year":"2015","journal-title":"J. Mol. Cell. Cardiol."},{"key":"2024061302355730400_DMM046375C18","doi-asserted-by":"publisher","first-page":"7","DOI":"10.1016\/j.stem.2019.12.004","article-title":"Toward the goal of human heart regeneration","volume":"26","author":"Sadek","year":"2020","journal-title":"Cell Stem Cell"},{"key":"2024061302355730400_DMM046375C19","doi-asserted-by":"publisher","first-page":"367","DOI":"10.1016\/j.euje.2005.01.007","article-title":"Evaluation of Tissue Doppler Tei index for global left ventricular function in mice after myocardial infarction: comparison with Pulsed Doppler Tei index","volume":"6","author":"Schaefer","year":"2005","journal-title":"Eur. J. Echocardiogr"},{"key":"2024061302355730400_DMM046375C20","doi-asserted-by":"publisher","first-page":"665","DOI":"10.1038\/ni0707-665","article-title":"Vagaries of conditional gene targeting","volume":"8","author":"Schmidt-Supprian","year":"2007","journal-title":"Nat. Immunol."},{"key":"2024061302355730400_DMM046375C21","doi-asserted-by":"publisher","first-page":"13702","DOI":"10.1073\/pnas.240471297","article-title":"Illegitimate Cre-dependent chromosome rearrangements in transgenic mouse spermatids","volume":"97","author":"Schmidt","year":"2000","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"2024061302355730400_DMM046375C22","doi-asserted-by":"publisher","first-page":"233","DOI":"10.1016\/S1097-2765(01)00295-7","article-title":"Self-excising retroviral vectors encoding the Cre recombinase overcome Cre-mediated cellular toxicity","volume":"8","author":"Silver","year":"2001","journal-title":"Mol. Cell"},{"key":"2024061302355730400_DMM046375C23","doi-asserted-by":"publisher","first-page":"20","DOI":"10.1161\/hh1301.092687","article-title":"Temporally regulated and tissue-specific gene manipulations in the adult and embryonic heart using a tamoxifen-inducible Cre protein","volume":"89","author":"Sohal","year":"2001","journal-title":"Circ. Res."},{"key":"2024061302355730400_DMM046375C24","doi-asserted-by":"publisher","first-page":"18033","DOI":"10.1074\/jbc.M113.541953","article-title":"Repression of cyclin D1 expression is necessary for the maintenance of cell cycle exit in adult mammalian cardiomyocytes","volume":"289","author":"Tane","year":"2014","journal-title":"J. Biol. Chem."},{"key":"2024061302355730400_DMM046375C25","doi-asserted-by":"publisher","first-page":"357","DOI":"10.1016\/S0894-7317(05)80111-7","article-title":"New index of combined systolic and diastolic myocardial performance: a simple and reproducible measure of cardiac function--a study in normals and dilated cardiomyopathy","volume":"26","author":"Tei","year":"1995","journal-title":"J. Cardiol."},{"key":"2024061302355730400_DMM046375C26","doi-asserted-by":"publisher","first-page":"1081","DOI":"10.1161\/CIRCULATIONAHA.115.019357","article-title":"Overexpression of Tbx20 in adult cardiomyocytes promotes proliferation and improves cardiac function after myocardial infarction","volume":"133","author":"Xiang","year":"2016","journal-title":"Circulation"},{"key":"2024061302355730400_DMM046375C27","doi-asserted-by":"publisher","first-page":"1208","DOI":"10.1161\/CIRCRESAHA.116.308544","article-title":"Loss of adult cardiac myocyte GSK-3 leads to mitotic catastrophe resulting in fatal dilated cardiomyopathy","volume":"118","author":"Zhou","year":"2016","journal-title":"Circ. Res."}],"container-title":["Disease Models &amp; Mechanisms"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1242\/dmm.046375","content-type":"unspecified","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/journals.biologists.com\/dmm\/article-pdf\/doi\/10.1242\/dmm.046375\/3484569\/dmm046375.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"http:\/\/journals.biologists.com\/dmm\/article-pdf\/doi\/10.1242\/dmm.046375\/2066031\/dmm_046375v1.pdf","content-type":"application\/pdf","content-version":"am","intended-application":"syndication"},{"URL":"https:\/\/journals.biologists.com\/dmm\/article-pdf\/doi\/10.1242\/dmm.046375\/3484569\/dmm046375.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,6,13]],"date-time":"2024-06-13T02:36:17Z","timestamp":1718246177000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.biologists.com\/dmm\/article\/13\/12\/dmm046375\/226451\/Myh6-driven-Cre-recombinase-activates-the-DNA"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,12,1]]},"references-count":27,"journal-issue":{"issue":"12","published-print":{"date-parts":[[2020,12,1]]}},"URL":"https:\/\/doi.org\/10.1242\/dmm.046375","relation":{},"ISSN":["1754-8411","1754-8403"],"issn-type":[{"value":"1754-8411","type":"electronic"},{"value":"1754-8403","type":"print"}],"subject":[],"published":{"date-parts":[[2020,12,1]]},"article-number":"dmm046375"}}