*4.15. Statistical Analysis*

Experiments were repeated in triplicate and results are displayed as the mean ± SE unless otherwise indicated. *p*-values were calculated using student's t-test unless otherwise specified.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/1422-0067/21/21/8317/s1, Figure S1: Transcription factor analysis, Table S1: E9.5-specific enhancer gene ontology terms, Figure S2: RNAscope showing *Plagl1* expression in the allantois and labyrinth, Table S2: E9.5 highly expressed, upregulated transcription factors, Figure S3: Disease ontology for downregulated genes, Table S3: Samples used for *Plagl1* expression in GDM placentas, Figure S4: PLAGL1 target gene and enhancer activity, Table S4: DESeq2 output, Table S5: List of primers used for RT-qPCR, Table S6: HTR-8/SVneo HISAT2 results, Table S7: Target enhancer primers.

**Author Contributions:** Conceptualization, R.R.S. and G.T.; Methodology, R.R.S. and G.T.; Validation, R.R.S., R.A.A. and H.K.; Formal Analysis, R.R.S., G.T.; Investigation, R.R.S., R.A.A., H.K., K.A.P., L.C.S.; Resources, K.A.P., L.C.S.; Data Curation, R.S.S.; Writing—Original Draft Preparation, R.R.S. and G.T.; Writing—Review & Editing, R.R.S., R.A.A., H.K., K.A.P., L.C.S., and G.T.; Visualization, R.R.S., G.T.; Supervision, G.T.; Project Administration, G.T.; Funding Acquisition, G.T. All authors have read and agreed to the published version of the manuscript.

**Funding:** Research reported in this publication was supported by the Eunice Kennedy Shriver National Institute of Child Health & Human Development of the National Institutes of Health under Award Number R01HD096083 (to GT) and Award Number R03HD090220 (to KAP). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

**Acknowledgments:** We would like to acknowledge Rachel Phillips and the Comparative Pathology Core at Iowa State University College of Veterinary Medicine for help with tissue fixation and performing RNAscope experiments, the Roy J. Caver High Resolution Microscopy Facility at Iowa State University for use of the Zeiss Observer microscope, and the Iowa State University DNA Facility for providing sequencing for RNA-seq experiments. We would also like to acknowledge the Research IT group at Iowa State University (http://researchit.las.iastate.edu) for providing servers and IT support.

**Conflicts of Interest:** The authors declare no conflict of interest.
