Electron Microscope Studies of the Microvilli of Hela Cells

Fisher, Harold W.; Cooper, Tracy

doi:10.1083/jcb.34.2.569

Cited by 75 publications

(36 citation statements)

References 14 publications

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“…FIV-infected CRFK cells produced abundant microvilli in the presence or absence of tetherin (Fig. 8A) with a morphology similar to that described previously for HeLa cells (12). While 0.1-m-diameter particles were noted in the regions rich in microvilli, the resolution of the CRFK-derived images made it difficult to distinguish conclusively electrondense virus-like particles from a cross-section through the tip of a microvillus (Fig.…”

Section: Resultssupporting

confidence: 72%

“…Oligonucleotide primers were synthesized corresponding to the predicted start (forward primer 5Ј-ATGGCACCTGCTTTTT TACCAC-3Ј) and stop (reverse primer 5Ј-TCAGGCCAGCAGAGCAACGAA-3Ј) codons of feline tetherin. Mya-1 cells were lysed (QIAshredder; Qiagen Ltd., Crawley, United Kingdom), and total RNA was prepared by guanidine-isothiocyanate lysis using an RNeasy Minikit (Qiagen Ltd., Crawley, United Kingdom) and reverse transcribed using a Transcriptor High Fidelity cDNA synthesis kit and oligo(dT) 12 primer (Roche Applied Science, Burgess Hill, United Kingdom). The feline tetherin (feTHN) cDNA was amplified using Phusion DNA polymerase [Finnzymes; New England BioLabs (UK) Ltd., Hitchin, United Kingdom] and its nucleic acid sequence determined using BigDye Terminator v1.1 cycle sequencing (Applied Biosystems, Life Technologies, Paisley, United Kingdom) followed by analysis performed using an Applied Biosystems 3730xl genetic analyzer and chromatogram analysis performed using the Chromas version 1.45 software package (Technelysium Pty.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Feline Tetherin Efficiently Restricts Release of Feline Immunodeficiency Virus but Not Spreading of Infection

Dietrich

McMonagle

Petit

et al. 2011

J Virol

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Innate resistance to retroviral infection and replication is induced by interferons (IFNs). IFN-inducible factors restricting viral replication include the cytidine deaminase APOBEC3G (40, 60) and the E3 ubiquitin ligase TRIM5 (1), both of which target replication primarily during the process of viral entry. A third IFN-inducible activity, tetherin (BST-2/ CD317/HM1.24), acts to restrict viral release (13,35,36,41,62). The importance of these factors in controlling viral replication is underlined by the requirement for lentiviral genomes to encode trans-acting countermeasures; lentiviral Vif proteins (33,54,55) and spumaviral Bet proteins (28, 42, 51) counteract APOBECs whereas HIV-1 Vpu, HIV-2 Nef, and HIV-2 and simian immunodeficiency virus (SIV) Envs may counteract tetherins (15,18,26,35,36,62,65).Tetherin is a type II single-pass transmembrane protein. It is anchored to the cell membrane by both N-terminal transmembrane domain and C-terminal glycophosphatidylinositol (GPI) anchors that are linked by an extracellular coiled-coil domain that promotes dimerization of adjacent tetherin molecules. Accordingly, tetherin in both the cell membrane and the envelope of the budding virus can prevent virion release either by direct cross-linking or by the formation of dimers between adjacent coiled-coil domains (41). The primary role for tetherin remains unclear; however, it is likely that, by trapping enveloped viruses at the cell surface, tetherin prevents the further dissemination of nascent virions. However, given the constitutive high-level expression of tetherin on plasmacytoid dendritic cells (pDC [type I IFN-producing cells]) (5), tetherin may play a more fundamental role in the initiation and perpetuation of a virus-specific immune response (58).The domestic cat lineage has faced multiple invasions by viruses from the family Retroviridae. In addition to an exogenous gammaretrovirus (feline leukemia virus [FeLV]), a lentivirus (feline immunodeficiency virus [FIV]), and a spumavirus (feline foamy virus [FFV]), cats also harbor the endogenous RD114 gamma retrovirus (47, 48) and full-length endogenous FeLVs (50). While lentiviruses have spread throughout the Felidae, from lions in Africa to pumas in North America and Pallas cats in Mongolia (61), the gamma retroviruses are restricted solely to domestic cats (3,4,47,48), although occasional cross-species transmission events have been recorded in Florida panthers (37) and Iberian lynxes (30). The limited distribution of the gamma retroviruses among felids suggests that they entered the domestic cat population after the divergence of the Felis lineage from the other felids circa 6.2 million years ago (19). The presence of three exogenous members and one endogenous member of the Retroviridae in domestic cats offers an intriguing insight into the retrovirus-host interaction. As cats express a truncated TRIM5 lacking a capsid-binding B30.2/SPRY domain (29), their ability to suppress retroviral replication may be impaired. If tetherin is to have a major role in the contro...

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Section: Resultssupporting

confidence: 72%

Section: Methodsmentioning

confidence: 99%

Feline Tetherin Efficiently Restricts Release of Feline Immunodeficiency Virus but Not Spreading of Infection

Dietrich

McMonagle

Petit

et al. 2011

J Virol

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“…One hypothesis is that the cell membrane affinity of sentan is dependent on the curvature of the membrane; as a result, sentan localization to the protrusions could be dependent on their diameter. Interestingly, the diameter of the distal portion of cilia is almost equivalent to the diameter of HeLa cell protrusions: 150 and ϳ120 -130 nm, respectively (Fisher and Cooper, 1967;Porter et al, 1974;Foliguet and Puchelle, 1986;Hosaka et al, 1993). These diameters are smaller than that of cilia axoneme (ϳ250 -300 nm) and larger than that of microvilli (ϳ80 nm) present on the apical surface of tracheal epithelial cells (Simionescu and Simionescu, 1976;Dalen, 1983); neither of these recruited adenovirus-overexpressed or native sentan, which supports the idea that sentan localization is dependent on the curvature of the membrane.…”

Section: Discussionmentioning

confidence: 99%

Sentan: A Novel Specific Component of the Apical Structure of Vertebrate Motile Cilia

Kubo

Yuba-Kubo

Tsukita

et al. 2008

MBoC

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Human respiratory and oviductal cilia have specific apical structures characterized by a narrowed distal portion and a ciliary crown. These structures are conserved among vertebrates that have air respiration systems; however, the molecular components of these structures have not been defined, and their functions are unknown. To identify the molecular component(s) of the cilia apical structure, we screened EST libraries to identify gene(s) that are exclusively expressed in ciliated tissues, are transcriptionally up-regulated during in vitro ciliogenesis, and are not expressed in testis (because sperm flagella have no such apical structures). One of the identified gene products, named sentan, was localized to the distal tip region of motile cilia. Using anti-sentan polyclonal antibodies and electron microscopy, sentan was shown to localize exclusively to the bridging structure between the cell membrane and peripheral singlet microtubules, which specifically exists in the narrowed distal portion of cilia. Exogenously expressed sentan showed affinity for the membrane protrusions, and a protein-lipid binding assay revealed that sentan bound to phosphatidylserine. These findings suggest that sentan is the first molecular component of the ciliary tip to bridge the cell membrane and peripheral singlet microtubules, making the distal portion of the cilia narrow and stiff to allow for better airway clearance or ovum transport. INTRODUCTIONMotile cilia and flagella are membrane-bound, microtubulecontaining cell surface projections that are differentiated by their length, movement characteristics, and numbers per cell (Haimo and Rosenbaum, 1981;Mitchell, 2007;Satir and Christensen, 2007). Flagella-containing cells generally have only one or two flagella, which are long motile structures that beat independently and exhibit an undulating motion. Conversely, cilia are generally much more numerous and are shorter motile projections with an oscillating to-and-fro motion. In humans, flagella are observed only in sperm cells, whereas motile cilia are observed on the respiratory epithelium, along the female reproductive tract, and on the ependymal cells lining the ventricles of the brain.Early studies using electron microscopy showed that the terminal end of mammalian motile cilia is quite distinct from that of sperm flagella (see Figure 6). At the terminal end of mammalian sperm flagella, peripheral doublet microtubules lose the outer B subfibers or separate into two singlet microtubules. Each singlet microtubule approaches the cell membrane, becomes electron dense and terminates successively. Only a few peripheral singlet subfibers continue to the tip of the sperm tail (Woolley and Nickels, 1985;Afzelius et al., 1995;Suzuki and Nagano, 2002). In contrast, the apical structure of mammalian cilia has a distinct fine structure at the termination site of the axonemal microtubules. The outer B subfibers of peripheral doublet microtubules terminate at the distal portion of cilia, and only the singlet A subfibers continue to the tip. T...

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“…These results may be interpreted as follows: reversible attachment was caused by long-range forces of the secondary minimum; irreversible attqchment was probably due to the stronger binding forces of the primary minimum and hence must have occurred via the agency of a salmonella adhesin. The calculations were based initially on the assumption that the HeLa cell surfaces were near planar whereas HeLa cells do produce filamentous surface projections (Fisher & Cooper, 1967;Pugh-Humphreys & Sinclair, 1970;Kihlstrom & Latkovic, 1978). Accommodation of this variable and others, however, did not appreciably alter the value of H or the conclusions.…”

Section: Discussionmentioning

confidence: 99%

The Invasion of HeLa Cells by Salmonella typhimurium: Reversible and Irreversible Bacterial Attachment and the Role of Bacterial Motility

1981

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The interactions which brought about the invasion of HeLa cells by Salmonella typhimurium consisted of a sequence of three phases. Initially, the motility of the bacteria facilitated their contact with the HeLa cells whereupon the bacteria became attached in a reversible manner (i.e. the bacteria could be removed readily by washing the HeLa cell monolayers with Hanks' Balanced Salt solution). The binding forces responsible for reversible attachment were probably the weak long-range forces of the secondary minimum level of attractive interactions between the bacterium and the HeLa cell. Reversible attachment was a necessary interlude before the bacteria became irreversibly attached to the surfaces of the HeLa cells (i.e. the bacteria were no longer removed by the washing procedure that removed the reversibly attached salmonellae). Irreversible attachment was prevented in solutions of low ionic strength; the forces responsible were probably those of the primary minimum generated between the HeLa cell and a bacterial adhesin which was capable of acting over only short distances between the reversibly attached bacterium and the HeLa cell (i.e. probably less than 15 nm). Only irreversibly attached bacteria proceeded to the third phase and were internalized by the HeLa cells.

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Electron Microscope Studies of the Microvilli of Hela Cells

Cited by 75 publications

References 14 publications

Feline Tetherin Efficiently Restricts Release of Feline Immunodeficiency Virus but Not Spreading of Infection

Feline Tetherin Efficiently Restricts Release of Feline Immunodeficiency Virus but Not Spreading of Infection

Sentan: A Novel Specific Component of the Apical Structure of Vertebrate Motile Cilia

The Invasion of HeLa Cells by Salmonella typhimurium: Reversible and Irreversible Bacterial Attachment and the Role of Bacterial Motility

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