Unique requirements for Ki-67 in mouse haematopoiesis

Ki-67 is a protein expressed in all dividing cells and assists in chromosome separation during cell division. High Ki-67 expression is most commonly associated with poor cancer prognoses, therefore, improved understanding of Ki-67’s function may lead to the development of new cancer treatments. To address the large gaps in our knowledge of Ki-67 function, we made a mouse genetically lacking Ki-67. We discovered that Ki-67 was not required for normal life but was specifically required for normal lymphocyte development. We linked Ki-67 expression to successful rearrangement of lymphocyte receptors, indicating Ki-67 has a unique role in immune cell development.