Islet-brain1/JNK-interacting protien-1 is required for early embryogenesisin mice

Islet-brain1/JNK-interacting protein-1 (IBl/JIP-1) is a scaffold protein th at organizes the JNK, MKK7, and MLK1 to allow signaling specificity. Target ed disruption of the gene MAPK8IP1 encoding IB1/JIP-1 in mice led to embryo nic death prior to blastocyst implantation. In culture, no IB1/JIP-1(-/-) e mbryos were identified indicating that accelerated cell death occurred duri ng the first cell cycles. IB1/JIP-1 expression was detected in unfertilized oocytes, in spermatozoa, and in different stages of embryo development. Th us, despite the maternal and paternal transmission of the IB1/JIP-1 protein , early transcription of the MAPK8IP1 gene is required for the survival of the fertilized oocytes.