Roles of LAP2 proteins in nuclear assembly and DNA replication: Truncated LAP2β proteins alter lamina assembly, envelope formation, nuclear size, and DNA replication efficiency in Xenopus laevis extracts

Tracey Michele Gant, Crafford A. Harris, Katherine Lee Wilson

Research output: Contribution to journalArticle

Abstract

Humans express three major splicing isoforms of LAP2, a lamin- and chromatin-binding nuclear protein. LAP2β and γ are integral membrane proteins, whereas α is intranuclear. When truncated recombinant human LAP2β proteins were added to cell-free Xenopus laevis nuclear assembly reactions at high concentrations, a domain common to all LAP2 isoforms (residues 1-187) inhibited membrane binding to chromatin, whereas the chromatin- and lamin- binding region (residues 1-408) inhibited chromatin expansion. At lower concentrations of the common domain, membranes attached to chromatin with a unique scalloped morphology, but these nuclei neither accumulated lamins nor replicated. At lower concentrations of the chromatin and lamin-binding region, nuclear envelopes and lamins assembled, but nuclei failed to enlarge and replicated on average 2.5-fold better than controls. This enhancement was not due to rereplication, as shown by density substitution experiments, suggesting the hypothesis that LAP2β is a downstream effector of lamina assembly in promoting replication competence. Overall, our findings suggest that LAP2 proteins mediate membrane-chromatin attachment and lamina assembly, and may promote replication by influencing chromatin structure.

Original languageEnglish (US)
Pages (from-to)1083-1096
Number of pages14
JournalJournal of Cell Biology
Volume144
Issue number6
DOIs
StatePublished - Mar 22 1999

Fingerprint

Nuclear Envelope
Xenopus laevis
DNA Replication
Chromatin
Lamins
Membranes
Protein Isoforms
lamina-associated polypeptide 2
Nuclear Proteins
Mental Competency
Carrier Proteins
Membrane Proteins

Keywords

  • Chromatin structure
  • Emerin
  • MAN
  • Nuclear envelope
  • Prereplication complex

ASJC Scopus subject areas

  • Cell Biology

Cite this

@article{7e3a9e56e28a469d9d7363b40d10a598,
title = "Roles of LAP2 proteins in nuclear assembly and DNA replication: Truncated LAP2β proteins alter lamina assembly, envelope formation, nuclear size, and DNA replication efficiency in Xenopus laevis extracts",
abstract = "Humans express three major splicing isoforms of LAP2, a lamin- and chromatin-binding nuclear protein. LAP2β and γ are integral membrane proteins, whereas α is intranuclear. When truncated recombinant human LAP2β proteins were added to cell-free Xenopus laevis nuclear assembly reactions at high concentrations, a domain common to all LAP2 isoforms (residues 1-187) inhibited membrane binding to chromatin, whereas the chromatin- and lamin- binding region (residues 1-408) inhibited chromatin expansion. At lower concentrations of the common domain, membranes attached to chromatin with a unique scalloped morphology, but these nuclei neither accumulated lamins nor replicated. At lower concentrations of the chromatin and lamin-binding region, nuclear envelopes and lamins assembled, but nuclei failed to enlarge and replicated on average 2.5-fold better than controls. This enhancement was not due to rereplication, as shown by density substitution experiments, suggesting the hypothesis that LAP2β is a downstream effector of lamina assembly in promoting replication competence. Overall, our findings suggest that LAP2 proteins mediate membrane-chromatin attachment and lamina assembly, and may promote replication by influencing chromatin structure.",
keywords = "Chromatin structure, Emerin, MAN, Nuclear envelope, Prereplication complex",
author = "Gant, {Tracey Michele} and Harris, {Crafford A.} and Wilson, {Katherine Lee}",
year = "1999",
month = "3",
day = "22",
doi = "10.1083/jcb.144.6.1083",
language = "English (US)",
volume = "144",
pages = "1083--1096",
journal = "Journal of Cell Biology",
issn = "0021-9525",
publisher = "Rockefeller University Press",
number = "6",

}

TY - JOUR

T1 - Roles of LAP2 proteins in nuclear assembly and DNA replication

T2 - Truncated LAP2β proteins alter lamina assembly, envelope formation, nuclear size, and DNA replication efficiency in Xenopus laevis extracts

AU - Gant, Tracey Michele

AU - Harris, Crafford A.

AU - Wilson, Katherine Lee

PY - 1999/3/22

Y1 - 1999/3/22

N2 - Humans express three major splicing isoforms of LAP2, a lamin- and chromatin-binding nuclear protein. LAP2β and γ are integral membrane proteins, whereas α is intranuclear. When truncated recombinant human LAP2β proteins were added to cell-free Xenopus laevis nuclear assembly reactions at high concentrations, a domain common to all LAP2 isoforms (residues 1-187) inhibited membrane binding to chromatin, whereas the chromatin- and lamin- binding region (residues 1-408) inhibited chromatin expansion. At lower concentrations of the common domain, membranes attached to chromatin with a unique scalloped morphology, but these nuclei neither accumulated lamins nor replicated. At lower concentrations of the chromatin and lamin-binding region, nuclear envelopes and lamins assembled, but nuclei failed to enlarge and replicated on average 2.5-fold better than controls. This enhancement was not due to rereplication, as shown by density substitution experiments, suggesting the hypothesis that LAP2β is a downstream effector of lamina assembly in promoting replication competence. Overall, our findings suggest that LAP2 proteins mediate membrane-chromatin attachment and lamina assembly, and may promote replication by influencing chromatin structure.

AB - Humans express three major splicing isoforms of LAP2, a lamin- and chromatin-binding nuclear protein. LAP2β and γ are integral membrane proteins, whereas α is intranuclear. When truncated recombinant human LAP2β proteins were added to cell-free Xenopus laevis nuclear assembly reactions at high concentrations, a domain common to all LAP2 isoforms (residues 1-187) inhibited membrane binding to chromatin, whereas the chromatin- and lamin- binding region (residues 1-408) inhibited chromatin expansion. At lower concentrations of the common domain, membranes attached to chromatin with a unique scalloped morphology, but these nuclei neither accumulated lamins nor replicated. At lower concentrations of the chromatin and lamin-binding region, nuclear envelopes and lamins assembled, but nuclei failed to enlarge and replicated on average 2.5-fold better than controls. This enhancement was not due to rereplication, as shown by density substitution experiments, suggesting the hypothesis that LAP2β is a downstream effector of lamina assembly in promoting replication competence. Overall, our findings suggest that LAP2 proteins mediate membrane-chromatin attachment and lamina assembly, and may promote replication by influencing chromatin structure.

KW - Chromatin structure

KW - Emerin

KW - MAN

KW - Nuclear envelope

KW - Prereplication complex

UR - http://www.scopus.com/inward/record.url?scp=0033594083&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0033594083&partnerID=8YFLogxK

U2 - 10.1083/jcb.144.6.1083

DO - 10.1083/jcb.144.6.1083

M3 - Article

C2 - 10087255

AN - SCOPUS:0033594083

VL - 144

SP - 1083

EP - 1096

JO - Journal of Cell Biology

JF - Journal of Cell Biology

SN - 0021-9525

IS - 6

ER -