Author information:
(1)Department of Orthodontics, Peking University School & Hospital of 
Stomatology, #22 Zhongguancun South Avenue, Beijing 100081, China; Department of 
Anatomy and Cell Biology, University of Pennsylvania, School of Dental Medicine, 
240 South 40(th) Street, Philadelphia, PA 19104, USA; Center for Craniofacial 
Molecular Biology, Ostrow School of Dentistry, University of Southern 
California, 2250 Alcazar Street, CSA 103, Los Angeles, CA 90033, USA.
(2)Center for Craniofacial Molecular Biology, Ostrow School of Dentistry, 
University of Southern California, 2250 Alcazar Street, CSA 103, Los Angeles, CA 
90033, USA.
(3)Department of Molecular Microbiology and Immunology, University of Southern 
California, 2011 Zonal Avenue, Los Angeles, CA 90033, USA.
(4)National Institute of Dental and Craniofacial Research, NIH, 30 Convent 
Drive, MSC 4352 Bethesda, MD 20892, USA.
(5)Laboratory of Tissue Regeneration and Immunology and Department of 
Periodontics, Capital Medical University School of Stomatology, #4 Tiantanxili 
Avenue, Beijing 100050, China.
(6)Department of Anatomy and Cell Biology, University of Pennsylvania, School of 
Dental Medicine, 240 South 40(th) Street, Philadelphia, PA 19104, USA; Center 
for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of 
Southern California, 2250 Alcazar Street, CSA 103, Los Angeles, CA 90033, USA.
(7)Department of Orthodontics, Peking University School & Hospital of 
Stomatology, #22 Zhongguancun South Avenue, Beijing 100081, China.
(8)Norris Medical Library, Keck School of Medicine, University of Southern 
California, 2003 Zonal Avenue, Los Angeles, CA 90033, USA.
(9)Department of Orthodontics, Peking University School & Hospital of 
Stomatology, #22 Zhongguancun South Avenue, Beijing 100081, China. Electronic 
address: yanhengzhou@gmail.com.
(10)Department of Anatomy and Cell Biology, University of Pennsylvania, School 
of Dental Medicine, 240 South 40(th) Street, Philadelphia, PA 19104, USA; Center 
for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of 
Southern California, 2250 Alcazar Street, CSA 103, Los Angeles, CA 90033, USA. 
Electronic address: songtaos@dental.upenn.edu.