title: Pi, a pre-B-cell-specific enhancer element in the immunoglobulin heavy-chain enhancer.
abstract: We have identified a new immunoglobulin heavy-chain enhancer element, designated pi, between the microE2 and microE3 elements. The pi enhancer element is transcriptionally active primarily during early stages of B-cell development but becomes virtually inactive during B-cell maturation at about the stage of immunoglobulin kappa light-chain gene rearrangement. Mutational analysis suggests that the pi element is crucial for immunoglobulin heavy-chain enhancer activity at the pre-B-cell stage but is almost irrelevant for enhancer activity at the mature B-cell or plasma-cell stage. The activity of the pi enhancer element correlates with the presence of an apparently pre-B-cell-specific protein-DNA complex. The similarity of the pi site to recognition sequences for members of the ets gene family suggests that the protein(s) interacting with the pi site most likely are ets-related transcription factors.
authors.affiliation: Department of Medicine, Beth Israel Hospital, Boston, Massachusetts 02215.
authors.forename: T A
authors.initials: TA
authors.lastname: Libermann
authors.forename: D
authors.initials: D
authors.lastname: Baltimore
mesh_terms: D016475:3T3 Cells; D000818:Animals; D001402:B-Lymphocytes; D001483:Base Sequence; D001665:Binding Sites; D005075:Biological Evolution; D002460:Cell Line; D003001:Cloning, Molecular; D004247:DNA; D004742:Enhancer Elements, Genetic; D006367:HeLa Cells; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D005810:Multigene Family; D009154:Mutation; D015183:Restriction Mapping; D015682:Retroviridae Proteins, Oncogenic / Q000235:genetics; D014157:Transcription Factors / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D007143:Immunoglobulin Heavy Chains; D015682:Retroviridae Proteins, Oncogenic; D014157:Transcription Factors; C050379:oncogene proteins v-ets; D004247:DNA