title: A second higher vertebrate B-type lamin. cDNA sequence determination and in vitro processing of chicken lamin B2.
abstract: The chicken nuclear lamina is composed of at least three proteins called lamins A, B1 and B2. In addition, putative precursors are transiently expressed during in vivo synthesis of lamins A and B2. Here we report the complete sequence of lamin B2 as it is deduced from a cloned cDNA. Comparison of lamin B2 with lamins A and B1 in the accompanying paper provides definitive proof for the existence of two structurally distinct chicken B-type lamins. Furthermore, we show that in vitro translation of transcripts derived from lamin A and lamin B2 cDNAs yielded polypeptides that were indistinguishable, by two-dimensional gel electrophoresis, from the putative in vivo precursors of lamins A and B2 respectively. However, whereas the lamin A precursor was stable, the translation product of the lamin B2 transcript was processed in the reticulocyte lysate to a polypeptide comigrating on two-dimensional gels with authentic mature lamin B2. This processing event could be inhibited by chelators of divalent cations, i.e. o-phenanthroline and EDTA. Our results indicate that the transiently expressed variant of lamin B2 represent a bonafide precursor, and that two distinct activities are involved in processing of newly synthesized lamins A and B2. Lamin precursors processing is discussed in relation to characteristic differences in the interactions of A and B-type lamins with the nuclear membrane.
authors: Institute for Cell Biology, ETH-Hönggerberg, Zurich, Switzerland.
authors: K
authors: K
authors: Vorburger
authors: C F
authors: CF
authors: Lehner
authors: G T
authors: GT
authors: Kitten
authors: H M
authors: HM
authors: Eppenberger
authors: E A
authors: EA
authors: Nigg
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D002645:Chickens / Q000235:genetics*; D004270:DNA, Circular / Q000235:genetics*; D034904:Lamin Type A; D034921:Lamin Type B; D034882:Lamins; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics*; D011061:Poly A; D014176:Protein Biosynthesis; D012313:RNA; D011817:Rabbits; D015183:Restriction Mapping
chemical_list: D004270:DNA, Circular; D034904:Lamin Type A; D034921:Lamin Type B; D034882:Lamins; D009687:Nuclear Proteins; D011061:Poly A; D012313:RNA