Sort the following events to reflect the order in which they typically take place during the reprogramming of fibroblasts to induced pluripotent stem cells. Your answer would be a four-letter string composed of letters A to D only, e.g. ADBC.
(A) Sustained endogenous expression of Oct4
(B) Gain of embryonic marker protein
(C) Loss of fibroblast-specific marker protein
(D) OSKM overexpression

Question

Sort the following events to reflect the order in which they typically take place during the reprogramming of fibroblasts to induced pluripotent stem cells. Your answer would be a four-letter string composed of letters A to D only, e.g. ADBC.
(A)	Sustained endogenous expression of Oct4
(B)	Gain of embryonic marker protein
(C)	Loss of fibroblast-specific marker protein
(D)	OSKM overexpression

Quizplus · Accepted Answer

Two major waves of new gene expression are induced by OSKM (Oct4, Sox2, Klf4, and Myc) overexpression: in the first wave, genes involved in cell proliferation, metabolism, and cytoskeletal organization are induced, and fibroblast-specific markers are lost; in the second wave, which occurs only in the subset of cells that have gained an embryonic marker protein, genes required for stem-cell maintenance and embryonic development (e.g. endogenous Oct4) are switched on. Overall, the majority of cells (~99%) fail to become induced pluripotent stem cells.

Sort the Following Events to Reflect the Order in Which