Annulate lamellae: comparison of antigenic epitopes of annulate lamellae membranes with the nuclear envelope.

Abstract

Abstract. Annulate lamellae (AL) are a membranous structure frequently observed in differentiating gametes and tumor cells. In spite of numerous morphological studies, the function and biochemical composition of this membrane system are not well understood. In this study, we have examined the AL membrane system of vinblastine-treated mouse L cells using immunocytochemistry and Western blot analysis. Our results show that antibodies directed against nuclear envelope lamins, i.e., lamins A, B, and C, did not cross react with constituents of the AL membrane system. Furthermore an AL-specific antibody failed to react with the nuclear envelope and reacted minimally producing only a background stain over other cellular components. The data suggest that the AL membrane system has a distinct molecular make-up that is antigenically distinct from that of other subcellular structures.NULATE lamellae (AL) ~ are a network of intracellular membranes that have been described in numerous studies over the past 30 years (11). These membranes are often observed in rapidly dividing cells, germ cells, and cells at the onset of differentiation (11,12,18,19). However, the function served by this membrane system has yet to be elucidated. This organelle consists of a parallel stack of membranous cisternae trimmed with dense staining fibrillar plaques. Characteristically, the membranes contain pores. These intramembranous pores are morphologically similar to those found in the nuclear envelope. This has led to the speculation that these two membrane systems are structurally and perhaps functionally related (18).In this study we have compared the antigenicity of the nuclear envelope and the AL membrane system with the hope of identifying epitopes common to both membrane systems. As a marker for the nuclear envelope we have used antibodies directed against the nuclear lamins. In recent years the nuclear lamins have been shown to be a highly conserved family of proteins associated with the inner aspect of the nuclear envelope (6, 15). Lamins A, B, and C have been purified and extensively characterized (5, 7). Each is believed to form part of a protein complex that structurally supports the envelope during mitosis (5). An immunocytochemical approach was used to determine whether the lamins are present in the AL membrane system. In addition an antibody specific for the AL membrane system was detected in a serum sample taken from a patient having lupus erythematosus. This AL specific antibody was used to determine the cellular distribution of AL antigens. Abbreviations usedin thispaper:AL, annulate lamellae; TEM, transmission electron microscopy. Materials and Methods Reagents Induction of AL MembranesMouse L cells were grown in RPMI 1640 supplemented with 10% FCS and 1% penicillin-streptomycin. Under standard conditions the cells were cultured to near-confluency. Afterwards, the cells were cultured in medium containing vinblastine sulfate (0.1 pg/ml) for 36 h. The cell cultures were then processed for either transmission electron microscopy ...

Nuclear pore complex proteins mark the implantation window in human endometrium

“…Moreover, membrane proliferation appeared to be dependent on the permanent farnesylation of B-type lamins (Prufert et al, 2004;Ralle et al, 2004), but this modification is removed from the more highly NCS enriched A-type lamins. Finally, the presence of lamins and only some nucleoporins sets NCSs apart from annulate lamellae, intact NPCs embedded in register in lamin-free stacks of smooth endoplasmic reticulum (Chen and Merisko, 1988). Consequently, NCSs are distinct from all these nuclear structures.…”

Cytologic assessment of nuclear and cytoplasmic O-linked N-acetylglucosamine distribution by using anti-streptococcal monoclonal antibodies.

“…The relatively weak cytoplasmic staining is consistent with biochemical determinations of intracellular O-GlcNAc distribution (22), but the punctate pattern is unexpected. The punctate distribution of cytoplasmic reactivity might represent "spare" nuclear pore complexes in annulate lamellae (27), nuclear transport factors, extranuclear nucleolar proteins (28) or transcription factors (e.g., NFkB; refs. 5 and 29), or endoplasmic reticulum-associated O-linked GlcNAc residues (23).…”

Nuclear pore complex assembly studied with a biochemical assay for annulate lamellae formation.

“…Several nucleoporinspecific antibodies as well as gold-labeled WGA recognize AL pores (Chen and Merisko, 1988;Allen, 1990;Dabauvalle et al, 1991). Moreover, nucleoplasmin-coated gold particles associate with the pores of both the nuclear envelope and AL (Feldherr et al, 1984), mimicking the binding step of nuclear import (Newmeyer and Forbes, 1988;Richardson et al, 1988).…”

“…One way to circumvent these constraints would be to study pore formation in annulate lamellae (Chen and Merisko, 1988;for review, see Kessel, 1992). Annulate lamellae (AL) 1 are found in the cytoplasm and consist of stacks of flattened membrane cisternae perforated by numerous and densely packed pore complexes lacking both chromatin and a lamina.…”