In this task, you are given a sentence. You are expected to recognize the name of gene or protein. Although there might be several correct answers, you need to write one of them.

 The Runt family transcription factor CBFalpha2 ( AML1 , PEBP2alphaB , or Runx1 ) is required by hematopoietic stem cells and expressed at high levels in T - lineage cells .
transcription factor

 MHC tetramers , which constitute a labeled MHC - peptide ligand suitable for binding to the Ag - specific receptor on T cells , provide a novel approach for the detection and characterization of such rare cells .
MHC tetramers

 Constitutive PI3 - K activity is essential for proliferation , but not survival , of Theileria parva - transformed B cells .

PI3 - K