Tracer and freeze fracture observations on developing tight junctions in fetal rat thyroid

Tice, Lois W.; Carter, R.L.; Cahill, Mary C.

doi:10.1016/0040-8166(77)90002-7

Cited by 52 publications

(22 citation statements)

References 25 publications

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“…The sites of low conductance may be the junctional regions constituted by up to 10strands. Regional variations in the number of strands of a given occluding junction have been observed in epithelia like the rabbit gallbladder (Claude & Goodenough, 1973), cultured mouse mammary gland (Pickett et al, 1975), and the fetal rat thyroid (Tice, Carter & Cahill, 1977). However, in these examples no evidence was obtained to correlate the heterogeneity in the number of strands of the occluding junctions with local variations in transepithelial conductance, as shown here for MDCK cultured monolayers.…”

Section: Discussionmentioning

confidence: 46%

Occluding junctions in a cultured transporting epithelium: Structural and functional heterogeneity

1980

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MDCK cells (epithelioid of renal origin) form monolayers which are structurally and functionally similar to transporting epithelia. One of these similarities is the ability to form occluding junctions and act as permeability barriers. This article studies the junctions of MDCK monolayers formed on a permeable and transparent support (a disk of nylon cloth coated with collagen) by combining two different approaches: (i) Scanning of the electric field: the disk is mounted as a flat sheet between two Lucite chambers and pulses of 20--50 microA cm-2 are passed across. The apical surface of the monolayer is then scanned with a microelectrode to detect those points where the current is flowing. This shows that the occluding junctions of this preparation are not homogeneous, but contain long segments of high resistance, intercalated with sites of high conductance. (ii) Freeze fracture electron microscopy: the junctions are composed of regions of eight to ten strands intercalated with others where the strands are reduced to one or two ridges. The sites of high conductance may correspond to those segments where the number of junctional strands is reduced to 1 or 2. It is concluded that the occluding junctions of MDCK monolayers are functionally and morphologically heterogeneous, with "tight" regions intermixed with "leaky" ones.

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Section: Discussionmentioning

confidence: 46%

Occluding junctions in a cultured transporting epithelium: Structural and functional heterogeneity

1980

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“…No obvious junctional strands and their networks could be found in the myelinated nerve. The linear arrangement of junctional particles observed in the present study was reminiscent of the intermediate stage of a developing tight junction of embryonic epithelial and mesothelial cells in various species MONTESANO, 1975;TICE et al, 1977;NAGANO and SUZUKI, 1976a;SUZUKI and NAGANO, 1979), and also of the tight junctions in some vascular endothelia (YEE and REVEL, 1975;SIMIONESCU et al, 1975SIMIONESCU et al, , 1976 Sertoli cells (GILULA et al, 1976;NAGANO and SUZUKI, 1976b) and the proximal convoluted tubule of the kidney (CLAUDE and GOODENOUGH, 1973) of adult animals. Thus, the mesaxonal tight junction is generally leaky or loose in structure.…”

Section: Discussionmentioning

confidence: 86%

Mesaxonal membrane junction of myelinated nerve in the central and peripheral nervous system.

Inokuchi

Higashi

1980

Arch. Histol. Jap., Arch. Histol. Jpn

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“…Therefore, one would expect that, if the strands of an occluding junction are cylindrical lipidic micelles in Hexagonal Phase II, they would suffer drastic alterations when temperature is changed by several decades (3 to 37~ (3) The strands of the occluding junctions usually appear in freezefracture replicas as ridges on the P face and grooves on the E face. Yet in many occluding junctions, in particular those of fast growing or developing tissues (Humbert, Montesano, Perrelet & Orci), 1976;Tice, Carter & Cahill, 1977) and in junctions that are being resealed with Ca 2+ after a treatment with EGTA (Meldolesi et al, 1978;Hoi Sang, Saier & Ellisman, 1979), ridges are fragmented and seem to be constituted not by continuous filaments, but by rows of particles. It was even suggested that the strands of the occluding junctions are in fact formed by alignment and fusion of particles that were previously scattered in the plane of the membrane and that were cross linked by glutaraldehyde during fixation (Montesano, Friend, Perrelet & Orci, 1975;Van Deurs & Luft, 1979).…”

Section: Introductionmentioning

confidence: 99%

Effect of temperature on the occluding junctions of monolayers of epithelioid cells (MDCK)

1984

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In previous works it was demonstrated that the monolayer of MDCK cells behaves as a leaky epithelium where the electrical resistance across reflects the sealing capacity of the occluding junction. In the present work we study whether this sealing capacity can be modified by temperature and whether this is accompanied by changes in the structure of the occluding junction. Monolayers were prepared on disks of nylon cloth coated with collagen and mounted as a flat sheet between two Lucite chambers. The changes in resistance elicited by temperature were large (306% between 3 and 37 degrees C), fast (less than 2 sec), and reversible. An Arrhenius plot of conductance versus the inverse of temperature shows a broken curve (between 22 and 31 degrees C), and the activation energies calculated (3.2 and 4.0 kcal X mol-1) fall within the expected values for processes of simple diffusion. The morphology of the occluding junction was evaluated in freeze-fracture replicas by counting the number of strands and the width of the band occupied by the junction every 133 nm. In spite of the change by 306% of the electrical resistance and the phase transition, we were unable to detect any appreciable modification of the morphology of the occluding junction. Since the freeze-fracture replicas also show a density of intramembrane particles (IMP) different in the apical from that in the basolateral regions of the plasma membrane, as well as differences between face E and face P, we also investigated whether this is modified by temperature. Cold increases the population of IMP, but does not affect their polarization with the incubation time it takes to elicit changes in electrical resistance.

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Tracer and freeze fracture observations on developing tight junctions in fetal rat thyroid

Cited by 52 publications

References 25 publications

Occluding junctions in a cultured transporting epithelium: Structural and functional heterogeneity

Occluding junctions in a cultured transporting epithelium: Structural and functional heterogeneity

Mesaxonal membrane junction of myelinated nerve in the central and peripheral nervous system.

Effect of temperature on the occluding junctions of monolayers of epithelioid cells (MDCK)

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