{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T06:24:08Z","timestamp":1790835848541,"version":"4.1.0"},"reference-count":38,"publisher":"MDPI AG","issue":"22","license":[{"start":{"date-parts":[[2022,11,15]],"date-time":"2022-11-15T00:00:00Z","timestamp":1668470400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100006769","name":"Russian Science Foundation","doi-asserted-by":"publisher","award":["22-15-00227"],"award-info":[{"award-number":["22-15-00227"]}],"id":[{"id":"10.13039\/501100006769","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Inducible Cre-dependent systems are frequently used to produce both conditional knockouts and transgenic mice with regulated expression of the gene of interest. Induction can be achieved by doxycycline-dependent transcription of the wild type gene or OH-tamoxifen-dependent nuclear translocation of the chimeric Cre\/ERT2 protein. However, both of these activation strategies have some limitations. We analyzed the efficiency of knockout in different tissues and found out that it correlates with the concentration of the hydroxytamoxifen and endoxifen\u2014the active metabolites of tamoxifen\u2014measured by LC-MS in these tissues. We also describe two cases of Cdk8floxed\/floxed\/Rosa-Cre-ERT2 mice tamoxifen-induced knockout limitations. In the first case, the standard scheme of tamoxifen administration does not lead to complete knockout formation in the brain or in the uterus. Tamoxifen metabolite measurements in multiple tissues were performed and it has been shown that low recombinase activity in the brain is due to the low levels of tamoxifen active metabolites. Increase of tamoxifen dosage (1.5 fold) and duration of activation (from 5 to 7 days) allowed us to significantly improve the knockout rate in the brain, but not in the uterus. In the second case, knockout induction during embryonic development was impossible due to the negative effect of tamoxifen on gestation. Although DNA editing in the embryos was achieved in some cases, the treatment led to different complications of the pregnancy in wild-type female mice. We propose to use doxycycline-induced Cre systems in such models.<\/jats:p>","DOI":"10.3390\/ijms232214077","type":"journal-article","created":{"date-parts":[[2022,11,16]],"date-time":"2022-11-16T02:24:53Z","timestamp":1668565493000},"page":"14077","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":31,"title":["Limitations of Tamoxifen Application for In Vivo Genome Editing Using Cre\/ERT2 System"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0157-2102","authenticated-orcid":false,"given":"Leonid A.","family":"Ilchuk","sequence":"first","affiliation":[{"name":"Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nina I.","family":"Stavskaya","sequence":"additional","affiliation":[{"name":"Institute of Gene Biology, Russian Academy of Sciences, 34\/5 Vavilov Street, 119334 Moscow, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8451-1216","authenticated-orcid":false,"given":"Ekaterina A.","family":"Varlamova","sequence":"additional","affiliation":[{"name":"Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia"},{"name":"Federal State Budgetary Institution \u201cN.N. Blokhin National Medical Research Center of Oncology\u201d, Ministry of Health of the Russian Federation, Kashirskoe Sh., 24, 115478 Moscow, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alvina I.","family":"Khamidullina","sequence":"additional","affiliation":[{"name":"Institute of Gene Biology, Russian Academy of Sciences, 34\/5 Vavilov Street, 119334 Moscow, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9080-5683","authenticated-orcid":false,"given":"Victor V.","family":"Tatarskiy","sequence":"additional","affiliation":[{"name":"Institute of Gene Biology, Russian Academy of Sciences, 34\/5 Vavilov Street, 119334 Moscow, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2398-0331","authenticated-orcid":false,"given":"Vladislav A.","family":"Mogila","sequence":"additional","affiliation":[{"name":"Institute of Gene Biology, Russian Academy of Sciences, 34\/5 Vavilov Street, 119334 Moscow, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ksenia B.","family":"Kolbutova","sequence":"additional","affiliation":[{"name":"Head Center of Hygiene and Epidemiology of Federal Medical Biological Agency of Russia, 1st Pekhotniy Pereulok, 6, 123182 Moscow, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sergey A.","family":"Bogdan","sequence":"additional","affiliation":[{"name":"Head Center of Hygiene and Epidemiology of Federal Medical Biological Agency of Russia, 1st Pekhotniy Pereulok, 6, 123182 Moscow, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alexey M.","family":"Sheremetov","sequence":"additional","affiliation":[{"name":"Head Center of Hygiene and Epidemiology of Federal Medical Biological Agency of Russia, 1st Pekhotniy Pereulok, 6, 123182 Moscow, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alexandr N.","family":"Baulin","sequence":"additional","affiliation":[{"name":"Head Center of Hygiene and Epidemiology of Federal Medical Biological Agency of Russia, 1st Pekhotniy Pereulok, 6, 123182 Moscow, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Irina A.","family":"Filatova","sequence":"additional","affiliation":[{"name":"Head Center of Hygiene and Epidemiology of Federal Medical Biological Agency of Russia, 1st Pekhotniy Pereulok, 6, 123182 Moscow, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yulia Yu.","family":"Silaeva","sequence":"additional","affiliation":[{"name":"Institute of Gene Biology, Russian Academy of Sciences, 34\/5 Vavilov Street, 119334 Moscow, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maxim A.","family":"Filatov","sequence":"additional","affiliation":[{"name":"Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alexandra V.","family":"Bruter","sequence":"additional","affiliation":[{"name":"Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia"},{"name":"Federal State Budgetary Institution \u201cN.N. Blokhin National Medical Research Center of Oncology\u201d, Ministry of Health of the Russian Federation, Kashirskoe Sh., 24, 115478 Moscow, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,11,15]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"64","DOI":"10.1177\/0300985810395725","article-title":"Early Embryonic Lethality in Genetically Engineered Mice: Diagnosis and Phenotypic Analysis","volume":"49","author":"Papaioannou","year":"2012","journal-title":"Vet. Pathol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1483","DOI":"10.1111\/jth.15299","article-title":"Intrauterine lethality in Tfpi gene disrupted mice is differentially suppressed during mid- and late-gestation by platelet TFPI\u03b1 overexpression","volume":"19","author":"Siebert","year":"2021","journal-title":"J. Thromb. 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