STRUCTURAL ORGANIZATION OF THE HUMAN GENE (LMNB1) ENCODING NUCLEAR LAMIN B1

We have determined the structural organization of the human gene (LMNB 1) that encodes nuclear lamin B1, an intermediate filament protein of the nuclear envelope. The transcription unit spans more than 45 kh and the transcription start site is 348 nucleotides upstream from the tra nslation initiation codon. Lamin B1 is encoded by 11 exons. Exon 1 cod es for the aminoterminal head domain and the first portion of the cent ral rod domain, exons 2 through 6 the central rod domain, and exons 7 through 11 the carboxyl-terminal tail domain of this intermediate fila ment protein. Intron positions are conserved in other lamin genes from frogs, mice, and humans but different in lamin genes from Drosophila melanogaster and Caenorhabditis elegans. In the region encoding the ce ntral rod domain, intron positions are also similar to those in the ge ne for an invertebrate nonneuronal cytoplasmic intermediate filament p rotein and the genes for most vertebrate cytoplasmic intermediate fila ment proteins except neurofilaments and nestin. (C) 1995 Academic Pres s, Inc.