The mouse ortholog of the human SMARCB1 gene encodes two splice forms

The human SMARCB1 gene (SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily b, member 1, previously named the INI1/h SNF5 gene) is a tumor suppressor gene located on chromosome 22q11.2 and is inactivated in malignant rhabdoid tumors. By using an EST-based approach, w e cloned two splice forms of the Smarcb1 gene in mouse and a longer splice form of the human ortholog, Proteins corresponding to the longer (385 as) a nd the shorter (376 aa) forms are 100% conserved between human and mouse. M eningiomas and schwannomas are tumors frequently deleting various regions o n chromosome 22, including the SMARCB1 locus. We therefore directly sequenc ed seven SMARCB1 exons (90% of the open reading frame) in search for mutati ons in 41 meningiomas and 23 schwannomas. No inactivating mutations were ob served, which suggests that the SMARCB1 gene is not involved in the pathoge nesis of these tumors. (C) 1999 Academic Press.