1 National Center of Biotechnology Information, National Library of Medicine, NIH, Bethesda, MD, 20894, USA.
2 Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Bethesda, MD, 20892, USA.
3 Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Bethesda, MD, 20892, USA. briano@niddk.nih.gov.
4 National Center of Biotechnology Information, National Library of Medicine, NIH, Bethesda, MD, 20894, USA. przytyck@ncbi.nlm.nih.gov.