Immunocytochemical identification of non-neuronal intermediate filament proteins in the developing Xenopus laevis nervous system

1988 ◽  
Vol 43 (2) ◽  
pp. 207-224 ◽  
Author(s):  
Ben G. Szaro ◽  
Harold Gainer
1998 ◽  
Vol 141 (3) ◽  
pp. 727-739 ◽  
Author(s):  
Gregory A. Elder ◽  
Victor L. Friedrich ◽  
Paolo Bosco ◽  
Chulho Kang ◽  
Andrei Gourov ◽  
...  

Neurofilaments (NFs) are prominent components of large myelinated axons and probably the most abundant of neuronal intermediate filament proteins. Here we show that mice with a null mutation in the mid-sized NF (NF-M) subunit have dramatically decreased levels of light NF (NF-L) and increased levels of heavy NF (NF-H). The calibers of both large and small diameter axons in the central and peripheral nervous systems are diminished. Axons of mutant animals contain fewer neurofilaments and increased numbers of microtubules. Yet the mice lack any overt behavioral phenotype or gross structural defects in the nervous system. These studies suggest that the NF-M subunit is a major regulator of the level of NF-L and that its presence is required to achieve maximal axonal diameter in all size classes of myelinated axons.


Development ◽  
1989 ◽  
Vol 105 (2) ◽  
pp. 279-298
Author(s):  
H. Herrmann ◽  
B. Fouquet ◽  
W.W. Franke

To provide a basis for studies of the expression of genes encoding the diverse kinds of intermediate-filament (IF) proteins during embryogenesis of Xenopus laevis we have isolated and characterized IF protein cDNA clones. Here we report the identification of two types of Xenopus vimentin, Vim1 and Vim4, with their complete amino acid sequences as deduced from the cloned cDNAs, both of which are expressed during early embryogenesis. In addition, we have obtained two further vimentin cDNAs (Vim2 and 3) which are sequence variants of closely related Vim1. The high evolutionary conservation of the amino acid sequences (Vim1: 458 residues; Mr approximately 52,800; Vim4: 463 residues; Mr approximately 53,500) to avian and mammalian vimentin and, to a lesser degree, to desmin from the same and higher vertebrate species, is emphasized, including conserved oligopeptide motifs in their head domains. Using these cDNAs in RNA blot and ribonuclease protection assays of various embryonic stages, we observed a dramatic increase of vimentin RNA at stage 14, in agreement with immunocytochemical results obtained with antibody VIM-3B4. The significance of very weak mRNA signals detected in earlier stages is discussed in relation to negative immunocytochemical results obtained in these stages. The first appearance of vimentin has been localized to a distinct mesenchymal cell layer underlying the neural plate or tube, respectively. The results are discussed in relation to programs of de novo synthesis of other cytoskeletal proteins in amphibian and mammalian development.


1985 ◽  
Vol 5 (10) ◽  
pp. 2575-2581 ◽  
Author(s):  
J A Winkles ◽  
T D Sargent ◽  
D A Parry ◽  
E Jonas ◽  
I B Dawid

We have determined the sequence of cloned cDNAs derived from a 1,665-nucleotide mRNA which transiently accumulates during Xenopus laevis embryogenesis. Computer analysis of the deduced amino acid sequence revealed that this mRNA encodes a 47-kilodalton type I intermediate filament subunit, i.e., a cytokeratin. As is common to all intermediate filament subunits so far examined, the predicted polypeptide, named XK70, contains N- and C-terminal domains flanking a central alpha-helical rod domain. The overall amino acid homology between XK70 and a human 50-kilodalton type I keratin is 47%; homology within the alpha-helical domain is 57%. The N-terminal domain, which is not completely contained in our cDNAs, is basic, contains 42% serine plus alanine, and includes five copies of a six-amino-acid repeating unit. The C-terminal domain has a high alpha-helical content and contains a region with sequence homology to the C-terminal domains of other type I and type III intermediate filament proteins. We suggest that different keratin filament subtypes may have different functional roles during amphibian oogenesis and embryogenesis.


2010 ◽  
Vol 24 (11) ◽  
pp. 4396-4407 ◽  
Author(s):  
Parvathi Rudrabhatla ◽  
Philip Grant ◽  
Howard Jaffe ◽  
Michael J. Strong ◽  
Harish C. Pant

1995 ◽  
Vol 108 (11) ◽  
pp. 3581-3590 ◽  
Author(s):  
J. Adjaye ◽  
U. Plessmann ◽  
K. Weber ◽  
H. Dodemont

The neuronal cytoplasmic intermediate filament (IF) protein HeNF70 of the gastropod Helix aspersa is identified by sequence analysis of the corresponding 4,600 bp cDNA isolated from a cerebral ganglion cDNA library. HeNF70 shares 60% sequence identity with the neuronal LoNF70 protein of the cephalopod Loligo pealei and only 36% identity with the Helix non-neuronal IF-A protein. All three molluscan IF proteins display the lamin-type extended coil 1b subdomain harbouring six additional heptads and all have long C-terminal sequences with substantial homology to the tail domains of nuclear lamins. The lamin-like tail domains of the two neurofilament proteins share a unique motif comprising 13 residues, which is absent from Helix IF-A and all other known non-neuronal IF proteins. HeNF70 is encoded by a 9.5 kb RNA transcript. The very long 7.2 kb 3′-untranslated sequence contains a unique 26 nucleotide repeat extending over 0.5 kb in its 5′-region. The HeNF70 mRNA is expressed at low abundancy in cerebral ganglia but not in any of the 13 non-neuronal tissues tested. In contrast, all tissues express at fairly high levels the same 4.6 and 4.2 kb mRNAs encoding the Helix non-neuronal IF-A/B proteins. Blot hybridisation studies on genomic DNA and ganglion mRNA with subprobes from the cloned HeNF70 cDNA, as well as sequence analysis of an RT-PCR generated partial cDNA encoding a putative HeNF60 protein, indicate at least two different neuronal IF genes in Helix.


1999 ◽  
Vol 112 (13) ◽  
pp. 2233-2240
Author(s):  
G.Y. Ching ◽  
R.K. Liem

Type IV neuronal intermediate filament proteins consist of alpha-internexin, which can self-assemble into filaments and the neurofilament triplet proteins, which are obligate heteropolymers, at least in rodents. These IF proteins therefore provide good systems for elucidating the mechanism of intermediate filament assembly. To analyze the roles of the head domains of these proteins in contributing to their differential assembly properties, we generated chimeric proteins by swapping the head domains between rat alpha-internexin and either rat NF-L or NF-M and examined their assembly properties in transfected cells that lack their own cytoplasmic intermediate filament network. Lalphaalpha and Malphaalpha, the chimeric proteins generated by replacing the head domain of alpha-internexin with those of NF-L and NF-M, respectively, were unable to self-assemble into filaments. In contrast, alphaLL, a chimeric NF-L protein generated by replacing the head domain of NF-L with that of alpha-internexin, was able to self-assemble into filaments, whereas MLL, a chimeric NF-L protein containing the NF-M head domain, was unable to do so. These results demonstrate that the alpha-internexin head domain is essential for alpha-internexin's ability to self-assemble. While coassembly of Lalphaalpha with NF-M and coassembly of Malphaalpha with NF-L resulted in formation of filaments, coassembly of Lalphaalpha with NF-L and coassembly of Malphaalpha with NF-M yielded punctate patterns. These coassembly results show that heteropolymeric filament formation requires that one partner has the NF-L head domain and the other partner has the NF-M head domain. Thus, the head domains of rat NF-L and NF-M play important roles in determining the obligate heteropolymeric nature of filament formation. The data obtained from these self-assembly and coassembly studies provide some new insights into the mechanism of intermediate filament assembly.


Development ◽  
1988 ◽  
Vol 103 (2) ◽  
pp. 279-287
Author(s):  
P. Tang ◽  
C.R. Sharpe ◽  
T.J. Mohun ◽  
C.C. Wylie

Immunocytochemical studies using a monoclonal anti-porcine vimentin antibody reveal a well-organized pattern of staining in Xenopus laevis oocytes, eggs and early embryos. The positions of Xenopus vimentin and desmin in two-dimensional (2D) polyacrylamide gels were first established by immunoblotting of muscle Triton extracts with anti-intermediate filament antibodies (anti-IFA), which cross-react with all intermediate filament proteins (IFPs). The anti-porcine vimentin reacts with vimentin and desmin in muscle 2D immunoblots, but only reacts with one polypeptide in oocyte blots in the position predicted for vimentin (Mr 55 × 10(3), pI 5.6). Using an anti-sense probe derived from a Xenopus vimentin genomic clone in RNase protection assays, we show that expression of vimentin begins in previtellogenic oocytes. The level of expression remains constant throughout oogenesis and in unfertilized eggs. These data suggest that vimentin is expressed in oocytes and eggs. Most interestingly, the immunocytochemical results also show that vimentin is present in the germ plasma of oocytes, eggs and early embryos. It is therefore possible that vimentin has an important role in the formation or behaviour of early germ line cells.


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