TECHNOLOGY REPORT Generation of a Mouse Model for a Conditional Inactivation of Gtf2i Allele Badam Enkhmandakh, 1 Chris Stoddard, 2 Kris Mack, 2 Wei He, 2 Deb Kaback, 2 Siu-Pok Yee, 2 and Dashzeveg Bayarsaihan 1 * 1 Center for Regenerative Medicine and Skeletal Development, Department of Reconstructive Sciences, University of Connecticut Health Center, Farmington, Connecticut 2 Gene Targeting and Transgenic Facility, University of Connecticut Health Center, Farmington, Connecticut Received 11 April 2016; Revised 15 May 2016; Accepted 16 May 2016 Summary: The multifunctional transcription factor TFII- I encoded by the Gtf2i gene is expressed at the two-cell stage, inner cell mass, trophectoderm, and early gas- trula stages of the mouse embryo. In embryonic stem cells, TFII-I colocalizes with bivalent domains and depletion of Gtf2i causes embryonic lethality, neural tube closure, and craniofacial defects. To gain insight into the function of TFII-I during late embryonic and postnatal stages, we have generated a conditional Gtf2i null allele by flanking exon 3 with loxP sites. Crossing the floxed line with the Hprt-Cre transgenic mice resulted in inactivation of Gtf2i in one-cell embryo. The Cre-mediated deletion of exon 3 recapitulates a genetic null phenotype, indicating that the conditional Gtf2i line is a valuable tool for studying TFII-I function during embryonic development. genesis 54:407–412, 2016. VC 2016 Wiley Periodicals, Inc. Key words: conditional; Gtf2i; TFII-I; mouse embryos; chromatin TFII-I is a ubiquitously expressed transcriptional factor involved in both basal transcription and signal-induced transduction activation or repression (Roy, 2007, 2012). The GTF2I gene encoding TFII-I is the prime candidate responsible for cognitive abnormalities in the Williams- Beuren syndrome and autism spectrum disorders (Mal- enfant et al., 2012; Sakurai et al., 2011). In developing mouse embryos, TFII-I exhibits distinct and dynamic expression pattern (Enkhmandakh et al., 2004; Fijal- kowska et al., 2010; Ohazama and Sharpe, 2007). Gtf2i is often subjected to alternative splicing, which gener- ates TFII-I isoforms with different activities and distinct biological roles (Makeyev and Bayarsaihan, 2009). Previously, we identified a set of developmental genes as direct TFII-I targets revealing the complexity of TFII-I-mediated processes associated with distinct regu- latory networks (Chimge et al., 2008; Enkhmandakh et al., 2009; Makeyev and Bayarsaihan, 2011; Makeyev and Bayarsaihan, 2013). Genome-wide mapping studies revealed TFII-I occupancy at multiple genomic sites in mouse embryonic stem (ES) cells and embryonic tissues (Bayarsaihan et al., 2012; Makeyev et al., 2012). More- over, many TFII-I-bound regions colocalize with H3K4me3/K27me3 bivalent chromatin in the pro- moters of lineage-specific genes (Adamo et al., 2015; Bayarsaihan, 2013; Makeyev et al., 2012). Interestingly, TFII-I appears to have specific roles in distinct phases of the mammalian cell cycle (Ashworth and Roy, 2009). TFII-I plays an inhibitory role in regulating genes that are essential in osteogenesis and moreover, it has the ability to intersect with the bone-specific transcription factor Runx2 and the retinoblastoma protein Rb (Lazeb- nik et al., 2009). Activation of PI3K/Akt signaling, which is sufficient to maintain the pluripotency of mouse ES cells, results in down-regulation of Gtf2i (Chimge et al., 2012). Moreover upregulation of Gtf2i leads to activation of a specific group of developmental genes during ES cell differentiation. * Correspondence to: Dashzeveg Bayarsaihan, Institute for Systems Genomics and Center for Regenerative Medicine and Skeletal Development, University of Connecticut Health Center, 262 Farmington Avenue, Farmington, CT 06030, USA. E-mail: dashzeveg@uchc.edu Contract grant sponsor: NIH, Contract grant number: R01DE017205. Published online 19 May 2016 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/dvg.22948 VC 2016 Wiley Periodicals, Inc. genesis 54:407–412 (2016)