A Late Transition in Somatic Cell Reprogramming Requires Regulators Distinct from the Pluripotency Network

• Published in: Cell stem cell Vol. 11; no. 6; pp. 769 - 782
• Main Authors: Golipour, Azadeh, David, Laurent, Liu, Yu, Jayakumaran, Gowtham, Hirsch, Calley L., Trcka, Dan, Wrana, Jeffrey L.
• Format: Journal Article
• Language: English
• Published: Cambridge, MA Elsevier Inc 07.12.2012; Cell Press
• Subjects: Animals; Biological and medical sciences; Cell Differentiation - genetics; Cell differentiation, maturation, development, hematopoiesis; Cell physiology; Cellular Reprogramming - genetics; Clone Cells; clones; Embryo, Mammalian - cytology; Fibroblasts - cytology; Fibroblasts - metabolism; Fundamental and applied biological sciences. Psychology; gene expression; Gene Expression Profiling; gene expression regulation; Gene Expression Regulation, Developmental; Gene Regulatory Networks - genetics; Mice; Molecular and cellular biology; Pluripotent Stem Cells - cytology; Pluripotent Stem Cells - metabolism; RNA, Messenger - genetics; RNA, Messenger - metabolism; somatic cells; Transcription Factors - metabolism; Transcriptome - genetics; transgenes; Transgenes - genetics; Cellular reprogramming; Somatic cell; Late
• ISSN: 1934-5909; 1875-9777; 1875-9777
• DOI: 10.1016/j.stem.2012.11.008

Reprogramming of somatic cells to a pluripotent state via expression of Oct4, Klf4, Myc, and Sox2 is a multistep process involving phased changes in gene expression. Here, we focus on the later stages of reprogramming, termed maturation and stabilization. We show that the stabilization phase and the acquisition of pluripotency are dependent on the removal of transgene expression late in the maturation phase. Clonal analysis of cells undergoing reprogramming revealed subsets of stabilization-competent (SC) and stabilization-incompetent (SI) cells. SC clones acquire a competency gene-expression signature late in the maturation phase. Functional analysis of SC signature genes identified enhancers of the transition to the stabilization phase and a distinct subset of genes required for the maintenance of pluripotency. Thus, the acquisition and maintenance of pluripotency are regulated by distinct molecular networks, and a specific regulatory program not previously implicated in reprogramming is required for the transition to transgene independence. [Display omitted] ► Transgenes repress phase progression during somatic cell reprogramming ► Over time, cells acquire competency to transition to iPSCs upon transgene withdrawal ► Clonal analysis identifies signatures associated with reprogramming competency ► Distinct networks regulate transition to and maintenance of pluripotency During reprogramming, only a subset of cells moving through the process are able to complete it, and to do so they require a distinct set of genes separate from the pluripotency network itself.