Gametogenesis: the playground of the developmental cytologist

1985 ◽  
Vol 86 ◽  
pp. 29-35
Author(s):  
C. C. J. Miller ◽  
J. G. Duckett ◽  
B. Kirkham
Keyword(s):  
Multilayered Structure ◽  
Intermediate Filament Protein ◽  
Protein Antigens ◽  
Ultrastructural Studies ◽  
System A ◽  
Alignment System ◽  
Homosporous Ferns ◽  
Filament Protein ◽  
Generating System

SynopsisDevelopmental ultrastructural studies have led to major advances in our understanding of key questions ranging from the causal basis for the alternation of generations and the role of the cytoskeleton in cellshaping processes to the phylogeny of archegoniate plants. Oogenesis is characterised by profound nuclearcytoplasmic interactions accompanied by striking changes in the egg mitochondria and plastids. At fertilization, egg penetration is a physical process and the plastids from the spermatozoids are excluded from the egg. Considerable dissimilarity between the shapes of the biflagellate spermatozoids of Lycopodium and Selaginella underlines their ancient separation. Equally striking differences in spermatozoid architecture argue against any direct phyletic link between heterosporous and homosporous ferns. Taxonomic variations between the spermatozoids of homosporous ferns suggests blepharoplast morphology to be a potentially rich source of new systematic data. Whilst there is general agreement that the multilayered structure is a cytoskeletal alignment system, a proposed shape-generating system situated near the nuclear envelope, which provides the force necessary for spermatozoid morphogensis, has not yet been identified. New fixation procedures have revealed hitherto overlooked filamentous elements associated with the nucleus. Whereas tests for actin were negative, immunoblotting suggests that these contain the intermediate filament protein antigens.

scholarly journals Role of synemin, an intermediate filament protein, in adult skeletal muscle (1102.25)

2014 ◽  
Vol 28 (S1) ◽  
Author(s):  
Karla Garcia‐Pelagio ◽  
Joaquin Muriel ◽  
Linda Lund ◽  
Meredith Bond ◽  
Robert Bloch
Keyword(s):  
Skeletal Muscle ◽  
Intermediate Filament ◽  
Intermediate Filament Protein ◽  
Adult Skeletal Muscle ◽  
Filament Protein

Structure and Assembly Properties of the Intermediate Filament Protein Vimentin: The Role of its Head, Rod and Tail Domains

1996 ◽  
Vol 264 (5) ◽  
pp. 933-953 ◽  
Author(s):  
Harald Herrmann ◽  
Markus Häner ◽  
Monika Brettel ◽  
Shirley A. Müller ◽  
Kenneth N. Goldie ◽  
...  
Keyword(s):  
Intermediate Filament ◽  
Intermediate Filament Protein ◽  
Filament Protein

scholarly journals Sarcolemmal Organization in Skeletal Muscle Lacking Desmin: Evidence for Cytokeratins Associated with the Membrane Skeleton at Costameres

2002 ◽  
Vol 13 (7) ◽  
pp. 2347-2359 ◽  
Author(s):  
Andrea O'Neill ◽  
McRae W. Williams ◽  
Wendy G. Resneck ◽  
Derek J. Milner ◽  
Yassemi Capetanaki ◽  
...  
Keyword(s):  
Intermediate Filament ◽  
Tibialis Anterior Muscle ◽  
Membrane Skeleton ◽  
Intermediate Filament Protein ◽  
Mouse Muscle ◽  
Intermediate Filament Proteins ◽  
Fast Twitch Muscle ◽  
Filament Protein ◽  
Fast Twitch

The sarcolemma of fast-twitch muscle is organized into “costameres,” structures that are oriented transversely, over the Z and M lines of nearby myofibrils, and longitudinally, to form a rectilinear lattice. Here we examine the role of desmin, the major intermediate filament protein of muscle in organizing costameres. In control mouse muscle, desmin is enriched at the sarcolemmal domains that lie over nearby Z lines and that also contain β-spectrin. In tibialis anterior muscle from mice lacking desmin due to homologous recombination, most costameres are lost. In myofibers from desmin −/− quadriceps, by contrast, most costameric structures are stable. Alternatively, Z line domains may be lost, whereas domains oriented longitudinally or lying over M lines are retained. Experiments with pan-specific antibodies to intermediate filament proteins and to cytokeratins suggest that control and desmin −/− muscles express similar levels of cytokeratins. Cytokeratins concentrate at the sarcolemma at all three domains of costameres when the latter are retained in desmin −/− muscle and redistribute with β-spectrin at the sarcolemma when costameres are lost. Our results suggest that desmin associates with and selectively stabilizes the Z line domains of costameres, but that cytokeratins associate with all three domains of costameres, even in the absence of desmin.

scholarly journals Resistin Activates p65 Pathway and Reduces Glycogen Content through Keratin 8

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Fengyun Wen ◽  
Qiao Xia ◽  
Hui Zhang ◽  
Haipeng Shia ◽  
Amin Rajesh ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Glycogen Content ◽  
Vital Role ◽  
Intermediate Filament Protein ◽  
Transcriptional Expression ◽  
Glycogen Accumulation ◽  
Inflammatory Conditions ◽  
Keratin 8 ◽  
Filament Protein

Resistin is associated with metabolic syndrome and inflammatory conditions. Many studies have suggested that resistin inhibits the accumulation of glycogen; however, the exact mechanisms of resistin-induced decrease in glycogen content remain unclear. Keratin 8 is a typical epithelial intermediate filament protein, but numerous studies suggest a vital role of K8 in glucose metabolism. However, it is still not known whether K8 participates in the mediation of resistin-induced reduction of cellular glycogen accumulation. In this study, we found that resistin upregulated expression of the p65 subunit of NF-κB, which led to the promotion of K8 transcriptional expression; in turn, the expression of K8 inhibited glycogen accumulation in HepG2 cells.

An immunoelectron microscopic examination of the intermediate filament protein, desmin, in exercise-damaged skeletal muscle

1991 ◽  
Vol 49 ◽  
pp. 14-15
Author(s):  
C.M. Waterman-Storer
Keyword(s):  
Skeletal Muscle ◽  
Eccentric Exercise ◽  
Intermediate Filament ◽  
Intermediate Filament Protein ◽  
Tension Development ◽  
Filament System ◽  
Exercise Muscle ◽  
Exercise Induced ◽  
Filament Protein

Intense exercise has been shown to produce pathological changes in normal skeletal muscle ultrastructure. Eccentric exercise (muscle lengthening during active tension development) in particular has been shown to cause the most severe muscle damage, and studies of both human and animal tissue following eccentric exercise have documented disruption to the contractile apparatus. The disruption originates at the Z-disc, which appears broadened, smeared, or totally disrupted, with Z-discs of adjacent myofibrils out of register and running a “zig-zag” course transversely across the fiber. This condition is known as Z-line streaming. Several researchers have implicated the disruption of the intermediate filament system in the etiology of exercise-induced Z-line streaming, as these filaments are believed to link adjacent myofibrils at the level of the Z-disc. The intermediate filaments are composed predominantly of the proteins desmin and vimentin. This study utilized immunoelectron microscopic localization of desmin in order to elucidate the role of the intermediate filament system in Zline streaming of eccentrically-exercised skeletal muscle.

scholarly journals The role of gigaxonin in the degradation of the glial-specific intermediate filament protein GFAP

2016 ◽  
Vol 27 (25) ◽  
pp. 3980-3990 ◽  
Author(s):  
Ni-Hsuan Lin ◽  
Yu-Shan Huang ◽  
Puneet Opal ◽  
Robert D. Goldman ◽  
Albee Messing ◽  
...  
Keyword(s):  
Intermediate Filament ◽  
Genetic Disorder ◽  
Giant Axon ◽  
Alexander Disease ◽  
Intermediate Filament Protein ◽  
Gene Encoding ◽  
Recessive Mutations ◽  
Proteasome Pathway ◽  
Filament Protein

Alexander disease (AxD) is a primary genetic disorder of astrocytes caused by dominant mutations in the gene encoding the intermediate filament (IF) protein GFAP. This disease is characterized by excessive accumulation of GFAP, known as Rosenthal fibers, within astrocytes. Abnormal GFAP aggregation also occurs in giant axon neuropathy (GAN), which is caused by recessive mutations in the gene encoding gigaxonin. Given that one of the functions of gigaxonin is to facilitate proteasomal degradation of several IF proteins, we sought to determine whether gigaxonin is involved in the degradation of GFAP. Using a lentiviral transduction system, we demonstrated that gigaxonin levels influence the degradation of GFAP in primary astrocytes and in cell lines that express this IF protein. Gigaxonin was similarly involved in the degradation of some but not all AxD-associated GFAP mutants. In addition, gigaxonin directly bound to GFAP, and inhibition of proteasome reversed the clearance of GFAP in cells achieved by overexpressing gigaxonin. These studies identify gigaxonin as an important factor that targets GFAP for degradation through the proteasome pathway. Our findings provide a critical foundation for future studies aimed at reducing or reversing pathological accumulation of GFAP as a potential therapeutic strategy for AxD and related diseases.

Sign in / Sign up

Export Citation Format

Share Document