title: [Detection of nuclear matrix and intermediate filament scaffold in Crypthecodinium cohnii].
abstract: Nuclear matrix (NM) and intermediate filament (IF) scaffold in primitive eukaryote Crypthecodinium cohnii were shown using selective extraction together with embedment-free electron microscopy, whole mount cell preparation and immunoblot techniques. There exists a delicate NM-IF network spreading over cytoplasm and nucleus in dinoflagellate cells, however, nuclear lamina is undeveloped. The diameter of NM fiber is about 3-5 nm and IF is 10 nm. Chromosomes are connected with NM filament network. Immunoblot analysis showed that dinoflagellate contained keratin-like polypeptides (63 kD and 67 kD) while mammalian lamin antibodies did not crossreact with dinoflagellate total protein. Our experiment results demonstrated that a framework similar to NM-IF scaffold in mammalian cell appeared in primitive eukaryote. We propose that: (1) NM-IF scaffold is not restrict to vertebrate cell, and it may be originated from early stages of eukaryote evolution; (2) Keratin is probably very conservative; (3) Compared with IF, lamina might appear late in evolution, and some of primitive characteristics of dinoflagellate nucleus may be related to the lack of lamina.
authors.affiliation: Department of Biology, Peking University, Beijing.
authors.forename: S T
authors.initials: ST
authors.lastname: Cai
authors.forename: Z H
authors.initials: ZH
authors.lastname: Zhai
authors.forename: C M
authors.initials: CM
authors.lastname: Zeng
authors.forename: J Y
authors.initials: JY
authors.lastname: Li
mesh_terms: D000818:Animals; D004141:Dinoflagellida / Q000166:cytology*; D006801:Humans; D007382:Intermediate Filaments; D015530:Nuclear Matrix