Life goes through incredible changes in the womb – but puberty has moments of wonder too. Inside our pubescent cells, as well as those of other animals, proteins called transcription factors alter which of our genes switch on or ‘express’ – organs develop, hair grows and hormones flood around our bodies. In this part of a pubescent mouse’s mammary gland – called the terminal end bud – cells (highlighted by a red stain) prepare to mature into the adult breast. A high-powered microscope spots a transcription factor called Foxp1 in the green-stained cells along the surface. Foxp1 lies dormant during early life, but switches on during puberty, along with other proteins, to help milk ducts grow out like branches from buds like these. Watching Foxp1 may reveal more about the control of development and growth, but also clues to why similar processes go awry in breast cancers.
Written by John Ankers
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