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 language | English (US) |
|---|---|
| Pages (from-to) | 1083-1096 |
| Number of pages | 14 |
| Journal | Journal of Cell Biology |
| Volume | 144 |
| Issue number | 6 |
| DOIs | |
| State | Published - Mar 22 1999 |
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Keywords
- Chromatin structure
- Emerin
- MAN
- Nuclear envelope
- Prereplication complex
ASJC Scopus subject areas
- Cell Biology
Cite this
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. / Gant, Tracey Michele; Harris, Crafford A.; Wilson, Katherine Lee.
In: Journal of Cell Biology, Vol. 144, No. 6, 22.03.1999, p. 1083-1096.Research output: Contribution to journal › Article
}
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 -