Answer Happy

How did Yamanaka et al. (2006) identify which transcription factors were sufficient to induce pluripotency in fibroblast cell cultures? They knew beforehand which transcription factors would be sufficient to induce pluripotency in fibroblasts and overexpressed them in embryonic stem cells to show they retained pluripotency much longer than usual. They screened thousands of factors in different cell lines and implanted them into fruit O fly embryos to see if they would develop into healthy flies. They collected embryonic stem cells from mice and performed high-throughput sequencing to determine which transcription factors were upregulated in embryonic stem cells relative to fibroblasts. They narrowed down a pool of 24 factors to 4 factors by overexpressing all 24 in fibroblasts and removing one by one to see if its absence would impede colony formation.
Filopodium is the region marked by which letter in the accompanying diagram of a growth cone? B Growth cone O Region C O Region D Region B O Region A Region E E