Pérez-Olivares, MercedesTrento, AlfonsinaRodriguez-Acebes, SaraGonzález-Acosta, DanielFernández-Antorán, DavidRomán-García, SaraMartinez Garcia, Maria DoloresLópez-Briones, TaniaTorroja, CarlosCarrasco, Yolanda RMéndez, JuanMoreno de Alborán, Ignacio2024-02-022024-02-022018-10EMBO Rep . 2018;19(10):e4577http://hdl.handle.net/20.500.12105/17423The Myc family of oncogenic transcription factors regulates myriad cellular functions. Myc proteins contain a basic region/helix-loop-helix/leucine zipper domain that mediates DNA binding and heterodimerization with its partner Max. Among the Myc proteins, c-Myc is the most widely expressed and relevant in primary B lymphocytes. There is evidence suggesting that c-Myc can perform some of its functions in the absence of Max in different cellular contexts. However, the functional in vivo interplay between c-Myc and Max during B lymphocyte differentiation is not well understood. Using in vivo and ex vivo models, we show that while c-Myc requires Max in primary B lymphocytes, several key biological processes, such as cell differentiation and DNA replication, can initially progress without the formation of c-Myc/Max heterodimers. We also describe that B lymphocytes lacking Myc, Max, or both show upregulation of signaling pathways associated with the B-cell receptor. These data suggest that c-Myc/Max heterodimers are not essential for the initiation of a subset of important biological processes in B lymphocytes, but are required for fine-tuning the initial response after activation.engVoRhttp://creativecommons.org/licenses/by-nc-nd/4.0/Amino Acid SequenceAnimalsB-LymphocytesBasic Helix-Loop-Helix Leucine Zipper Transcription FactorsCell DifferentiationDNA ReplicationDNA-Binding ProteinsDimerizationHelix-Loop-Helix MotifsHumansLeucine ZippersMiceProtein BindingProto-Oncogene Proteins c-mycTranscriptional ActivationAttribution-NonCommercial-NoDerivatives 4.0 Internacional30126925191010.15252/embr.2018457701469-3178EMBO reportsopen access