| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Division of Endocrinology (P.S.K., S.M., B.L.) Department of
Medicine University of Cincinnati and Veterans Affairs Medical
Center Cincinnati, Ohio 45267
Graduate Program in Cell
and Molecular Biology (P.S.K., S.M.) Department of Cell Biology
University of Cincinnati College of Medicine Cincinnati, Ohio
45267
Center for Experimental Animal Science (M.D.,
C.-G.J., J.-M.C., T.M., T.A.) Nagoya City University Medical
School Nagoya, Aichi 467-8601, Japan
Department of
Laboratory Animal Science (S.-i.F.) Kitasato University School of
Medicine Sagamihara, Kanagawa 228-8555, Japan
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONRESULTSDISCUSSIONMATERIALS AND METHODSREFERENCES |
|---|
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONRESULTSDISCUSSIONMATERIALS AND METHODSREFERENCES |
|---|
1:3,000–4,000 newborns, caused either by thyroid dysgenesis
(80%) or dyshormonogenesis (20%). Although uncommon,
qualitative or quantitative defects of Tg are an established cause of
CHG (1). Although the precise molecular mechanism has not been well
established in most cases, at least in several reports, a common defect
appears to be the presence of misfolded mutant Tg that accumulates
inside the cell, unable to reach its final destination (2, 3). Normal
Tg must first be folded and assembled into its proper tertiary and
quaternary structure in the rough endoplasmic reticulum (ER) before it
can be exported along the distal secretory pathway, ultimately to an
extracellular space known as the colloid lumen, where it is iodinated
and stored. Thus, perturbations in the folding of nascent Tg can often
lead to defective intracellular transport of Tg (4). During the past,
the structural properties of the Tg have been well characterized (5): a
660-kDa glycoprotein that is secreted as a homodimer to serve as the
unique peptide backbone on which thyroid hormones are synthesized. As
the major secretory product of the thyrocytes, Tg typically accounts
for as much as 50% of total protein in the thyroid gland. The WIC-rdw rat, established from a closed colony of Wistar-Imamichi (WIC) rats as a spontaneous mutant exhibiting congenital dwarfism (rdw), is inherited as an autosomal recessive (6). Although the initial reports of reduced circulating levels of both GH and PRL suggested hypopituitarism in the WIC-rdw rat (7, 8, 9, 10), elevated TSH levels and the reduced level of T3 and T4 pointed toward a primary defect in thyroid hormone production (11). The latter has been supported by several recent studies which showed the restoration of not only their normal growth but also their normal serum levels of all pituitary hormones after the administration of T4 (8), feeding of extracts of the bovine thyroid (S-i. Furudate, unpublished data), or normal thyroid transplantation (S-i. Furudate, unpublished data). A recent morphological study of WIC-rdw thyrocytes further revealed dilated ER and reduced secretory granules as well as very low levels of Tg in the colloid lumen (12). These and other observations have strongly suggested that the dwarfism is attributable to a primary defect of the thyroid and not of the pituitary. Moreover, it was recently reported (13) that the molecular chaperones were markedly elevated in the WIC-rdw rat thyroid, similar to the cog/cog mouse that was defective in Tg export (4), thus exhibiting many features of an endoplasmic reticulum storage disease [ERSD (3)]. Interestingly, in a dramatic contrast to most human patients and animal models of CHG, histological analysis revealed a surprisingly hypoplastic thyroid gland that was smaller than the normal control despite elevated circulating levels of TSH in the WIC-rdw rat (11).
In the present study, in identifying the gene responsible for the observed phenotype, the rdw locus was mapped to the rat chromosome (Chr) 7 and found to be identical to the Tg gene locus, thus prompting our investigation to focus on the Tg gene. Additional studies revealed that the Tg protein level was reduced in the WIC-rdw thyroid, yet the transcripts of the Tg gene were similar in size and quantity, suggesting a possible defect in the Tg molecule. Consequently, a search for the mutation of the Tg gene revealed a single nucleotide (nt) substitution that cause a Gly to Arg change at a position that is highly conserved in other species including the human, mouse, and bovine. Here we provide solid evidence that a missense mutation in the Tg gene is indeed responsible for the nongoitrous congenital primary hypothyroidism in the WIC-rdw rat.
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONRESULTSDISCUSSIONMATERIALS AND METHODSREFERENCES |
|---|
). The rat Tg gene locus has
already been assigned to Chr 7 using somatic cell hybrid analysis,
although its detailed location was unknown (14). Since it was reported
that the mutations in the Tg gene caused Tg deficiency in
several animal models, we continued to map the rat Tg gene
locus using the same BC genetic panel. Using previously elucidated
information on the exon-intron structure of the rat Tg gene
(15), Tg gene introns were sequenced, revealing a G to A
substitution at nt 764 in intron 2 of the WIC-rdw rat
Tg gene as compared with that of the BN rat. This nt
substitution caused loss of a recognition site for the restriction
enzyme Cac8I. When the PCR product of the Tg gene
intron 2 (1,050 bp) from the BN rat was digested with Cac8I,
five DNA fragments (394, 356, 245, 35, and 20 bp) were observed as
predicted by the sequence analysis of intron 2, which contained four
Cac8I recognition sites. In Fig. 2, lane 2, only three bands (394, 356,
and 245 bp) were observed in the BN normal rat sample, since two short
fragments (20 and 35 bp) ran off the gel (not shown). However, in the
homozygous WIC-rdw rat samples, the band of 245 bp
(open arrow) was converted to a 280-bp band (245 + 35 bp;
closed arrow) due to the loss of one of the Cac8I
sites (Fig. 2, lane 3). The genotype of the Tg
gene was further determined by the presence of the 245-bp and 280-bp
bands in all the BC samples (Fig. 2, lanes 4–7). These mapping results
indicated that the Tg gene locus was identical to the
rdw locus (Fig. 1). The full-length sequence of the rat
Tg gene intron 2 has been submitted to GenBank (accession
number, AF221623).
|
|
, the transcripts of the Tg
gene were normally detected in the WIC-rdw thyroid. The
similar size and abundance of the WIC-rdw rat Tg
mRNA (8.5 kb) in comparison to the F344 wild-type (F344-wt) normal
control further excluded the possibility of a gross gene deletion, a
quantitative defect in transcription, or Tg mRNA
instability.
|
). The 330-kDa band
representing the intact Tg was significantly reduced in the
WIC-rdw rat. This band was verified to be the Tg protein by
loading the purified human and mouse Tg sample on the same gel (not
shown) and by Western blotting using antirat Tg antibody (Fig. 4B). Of
note, several lower mol wt bands were significantly elevated in the
WIC-rdw rat thyroid, which likely represent GRP94 (Fig. 4A, p95) BiP/GRP78 (Fig. 4A p75), and other ER resident proteins (not
shown) as reported previously (13). The elevated levels of these ER
molecular chaperones, which are essential in assisting in the folding
of many nascent polypeptides, in both the heterozygous and homozygous
rat thyroids (Fig. 4B, lanes 2 and 3, respectively), further
suggested that the WIC-rdw rat appeared to exhibit an
ERSD-like feature previously described in the cog/cog mouse
(4) and human patients with CHG (16). Together, these observations were
consistent with the possibility that the rdw mutation could
be a point mutation in the Tg gene as in the
cog/cog mouse or several human families (2).
|
). From these, the complete sequence of
the WIC-rdw rat Tg cDNA was determined (Fig. 5) and compared with that of the F344-wt
rat (GenBank accession number, AF221622). Although the full-length
sequence information on the human, mouse, and bovine Tg
cDNAs are available (17, 18, 19), that of the normal rat Tg
cDNA has not yet been reported. Therefore, it was necessary to sequence
the normal (F344-wt) rat Tg cDNA in its entirety as well.
The rat Tg cDNA contained a 8,307-bp open reading frame
(ORF), which encoded a protein containing 2,768 amino acids, showing
92.5%, 77.7%, and 75.2% homology with the mouse, human, and bovine
Tg cDNA, respectively. The predicted primary structure of
the rat Tg showed 90.4%, 73.3%, and 71.0% homology with those of the
mouse, human, and bovine Tg, respectively (not shown). As shown in
Figs. 5 and 6, there was a single nt
substitution, G6958C, that caused a single amino acid substitution,
G2320R, in the C-terminal region of the protein. The glycine at
position 2320 and the surrounding residues are highly conserved among
other species (Fig. 7), suggesting that
the rdw mutation likely represents a missense mutation
associated with a structural and/or functional alteration of the Tg
polypeptide and not just a single nt polymorphism (SNP). Highly
homologous to the intact acetylcholinesterase (AChE), the C-terminal
fifth of the Tg protein, which contains the rdw mutation,
was previously hypothesized to contain domain(s) that may be
structurally important in the Tg dimerization (20). In support of this
hypothesis, G2320 (Fig. 7, arrowhead) appeared to be
absolutely conserved not only in other Tgs and AChE but also in other
functionally unrelated proteins that share primary structural
similarities.
|
|
|
|
). In
contrast to the RT-PCR product from the WIC-rdw rat
Tg, which was the only one resistant to NIaIV,
those from other inbred strains including the WIC-+/+ rat were cleaved
into the two expected fragments of 117 and 143 bp (Fig. 8, lanes 2–3
and 5–8). Consistent with its genotype, the WIC-rdw/+ rat
showed both undigested and digested bands (Fig. 8, lane 9).
|
). In contrast, only the normal Tg was
found in the secreted media, suggesting that the rdw
mutation prevented the normal export of Tg (Fig. 9B) by rendering the
protein incompetent for intracellular transport, very similar to the
cog Tg (Fig. 9). As in other models of defective Tg
trafficking, the rdw Tg was retained inside the ER in both
primary WIC-rdw thyrocytes and COS-7 cells that were
transfected with the Tg cDNA containing the rdw
mutation (our unpublished data).
|
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONRESULTSDISCUSSIONMATERIALS AND METHODSREFERENCES |
|---|
Arg
substitution occurred at aa position 2,320, which was strictly
conserved not only in other rat and mouse inbred strains but also in
other mammalian species including human and bovine. 3) The parental
normal rat strain, WIC-+/+, showed no substitution at codon 2,320, and
the WIC-+/rdw rats showed heterozygous genotype at codon
2,320. 4) Transient expression of the full-length mouse Tg
cDNA containing the rdw mutation, showing the intracellular
presence of the intact Tg which was unable to be secreted, provided the
confirmation that rdw mutation was indeed responsible for
the observed phenotype. Northern blotting and SDS-PAGE analysis of the WIC-rdw rat thyroid homogenates revealed that the transcripts of the mutated Tg gene were not different from those of the wild type with respect to their size and amount. In fact, the Tg mRNA level was modestly elevated in the WIC-rdw thyrocytes, probably reflecting the increased thyroid stimulating effect of the elevated circulating TSH level, yet the amount of the 330-kDa Tg protein was reduced in the WIC-rdw thyroid. Several likely explanations merit consideration. For one, it may be that the missense substitution from a smaller neutral aa, glycine, to a larger basically charged aa, arginine, within a highly conserved domain, may have caused a substantial conformational change in the C-terminal region of Tg protein. As for most other disease-causing mutant proteins, such change often leads to structural instability that renders the protein highly susceptible to aggregation and/or proteolysis. This was in part supported by the experimental observation that the rdw Tg was quite prone to proteolysis when the thyroid follicles were lysed under nondenaturing conditions, even in the presence of a full battery of lysosomal protease inhibitors (our unpublished data). On the other hand, when the thyroid follicles were lysed in denaturing and reducing buffer at boiling temperature, one of the most potent conditions for inhibiting lysosomal protease activities, a greater amount of the rdw Tg was recovered after SDS-PAGE. To verify this hypothesis, further experiments utilizing limited proteolysis will be helpful.
Another plausible explanation for the reduced level of Tg protein in
the WIC-rdw thyroid is the inhibition of the translation
initiation by the presence of the malfolded proteins in the ER, as a
part of the unfolded protein response (UPR). In all eukaryotes, the
accumulating malfolded or misfolded proteins in the ER are increasingly
bound by several molecular chaperones including BiP/GRP78.
Consequently, as the available level of free or unbound BiP/GRP78
falls, a transmembrane kinase known as IRE-1p/ERN-1p is activated,
triggering the ER-UPR pathway that results in the transcriptional
induction of multiple ER chaperone genes (21). These molecular
chaperones then act to reduce the potential harm posed by the misfolded
mutant proteins that are prone to aggregation (3). At the same time,
the ER-UPR pathway activates another ER resident transmembrane protein
kinase or PERK/PEK, which phosphorylates the eukaryotic translation
initiation factor or eIF2
that eventually leads to the attenuation
of translation (22). Together, the elevated levels of ER chaperones and
the reduction in the continued synthesis of the misfolded mutant
proteins serve to minimize the toxic accumulation of potentially
harmful aggregates of misfolded proteins, thereby enhancing the
probability of cell survival.
Several mutations in the human (2, 23, 24, 25, 26, 27), mouse (20), bovine (28),
and goat Tg genes (29) have been elucidated at the molecular
level. It is interesting to compare the rdw mutation with
the recently identified cog mutation in the congenital
goiter mouse (20). The cog Tg gene also contained a single
nt change that resulted in a missense mutation, L2263P, located near
the N-terminal side of the rdw mutation. Both mutations are
associated with the marked accumulation of the chaperone proteins,
observed in other ERSDs involving mutant secretory proteins (3).
Additional similarities include normal sizes and amounts of the
Tg gene transcripts in both mutant thyrocytes, full-length
Tg proteins that exhibited increased susceptibility to proteolysis, as
well as the decreased synthesis and impairment of intracellular
transport of both mutants. Moreover, although not as striking as the
conservation of residues flanking the cog mutation, the
region surrounding G2320, especially on its C-terminal side, appears to
be also well conserved (Fig. 7
) not only among Tgs from different
species but also among other homologous proteins. Since the latter,
which include neuroligin, a novel neuronal cell surface protein
important in cell-cell interactions (30) and AChE, are functionally
unrelated to Tg, it may be that the homology stems from their
conformational similarities. In this case, substituting a positively
charged arginine for a smaller, hydrophobic G2320, which appears to be
absolutely conserved (Fig. 7, arrowhead), may lead to
structural instability. Confirming such a possibility will require
additional studies.
Finally, despite many similarities between the rat and mouse models of
Tg deficiency, there is one important difference that stands out
between the two models: the size of the their thyroid glands. In the
cog/cog mouse (and in several human patients with CHG), the
constant TSH stimulation that occurs in primary hypothyroidism
leads to the development of massive goiter that eventually compensates
for the quantitative defect in hormonogenesis. It appears that a very
small fraction of the cog Tg, which has been shown to be a
temperature-sensitive mutant (4), is able to reach the distal secretory
pathway to form thyroid hormones. The absence of this compensatory
response in the WIC-rdw rat may in part explain the severity
of the dwarfism and infertility in the adult rat, compared with the
cog/cog mouse. All previously reported mutations in the
Tg gene in other species caused goitrogenesis, yet the
rdw mutation was associated with a hypoplastic thyroid gland
(11, 12). Although the reason for this phenomenon remains unknown, it
is intriguing to consider the possibility that the rdw
mutation may be toxic to the host thyrocytes. Hence, comparing the
intracellular fates of the cog and the rdw Tgs as
well as their interactions with the essential components of the ER-UPR
pathway may provide new insights into how mutant proteins exert their
toxic effects on the host cells. On the contrary, cytotoxic effect of
the rdw mutation would be difficult to reconcile with the
autosomal recessive nature of the rdw phenotype. Additional
experiments are clearly needed to determine the mechanism by which
WIC-rdw heterozygous rat thyrocytes expressing the mutant Tg
protein avoid the same fate observed in the homozygous rat. Along this
line, 1-antitrypsin (AAT) deficiency, which is generally regarded as
an autosomal recessive, has been observed as an autosomal dominant in
some patients as well as in the transgenic animal model (3, 31).
Although most of these patients suffer from juvenile pulmonary
emphysema, only the patients with a specific mutation in the
AAT gene known as the Z-variant are additionally at risk for
hepatocellular damage leading to liver cirrhosis. Thus, the
susceptibility of each mutant to intracellular degradation may hold the
key in determining the potential cellular toxicity of the various
mutant proteins.
In conclusion, we have shown that the G2320R missense mutation is indeed responsible for the congenital hypothyroidism and dwarfism in the WIC-rdw rat, which will be useful for future investigation of the relationship of Tg protein structure with its stability, transport, and glycosylation mechanisms.
|
MATERIALS AND METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONRESULTSDISCUSSIONMATERIALS AND METHODSREFERENCES |
|---|
Mapping of the Rat Tg Gene Locus
The Tg gene intron 2 was amplified by PCR with
primers 5'-AGCAGGATGAATATGTTCCA-3' and 5'-ATCCACACACCAGCAAGATT-3'.
Amplified DNA fragments that were digested with 0.25 U of
Cac8I (New England Biolabs, Inc., Beverly, MA)
were analyzed in 6% polyacrylamide gels containing 90
mM Tris-borate and 2 mM
EDTA. DNA bands were visualized by staining with 0.5 µg/ml ethidium
bromide solution. Genotypes of the Tg gene were determined
by the presence or absence of 280-bp and 245-bp bands (see Fig. 2).
Linkage analysis was performed using Map Manager v2.6.5.
Detection of the Tg Gene Transcripts
The Tg gene transcripts were detected by Northern
blotting. Poly(A)+ RNAs were purified from total
RNAs of F344-wt and WIC-rdw rat thyroids using oligo(dT)
cellulose type 7 (Amersham Pharmacia Biotech,
Buckinghamshire, UK). Aliquots of 2 µg of
poly(A)+ RNA were denatured in 50% formamide,
2.2 M formaldehyde at 65 C for 10 min,
electrophoresed in 1% agarose gels containing 2.2
M formaldehyde, and transferred onto
Hybond-N+ membranes (Amersham Pharmacia Biotech). The poly(A)+ RNAs were
immobilized on the membranes by heating at 80 C for 2 h.
Prehybridization and hybridization of the membranes were performed in
buffer containing 50% formamide, 5 x standard saline citrate
solution (SSC), 5 x Denhardt’s solution, and 0.5% SDS at 45 C
for 16 h. The 5'-end of the Tg cDNA fragment was
amplified by RT-PCR and used as a probe. The probe was labeled with
-32P dCTP using a Rediprime Kit (Amersham Pharmacia Biotech). Membranes were washed in buffer containing
0.1 x SSC and 0.1% SDS and exposed to X-AR film
(Kodak, Rochester, NY) at -70 C for 24 h.
Detection of the Tg Protein
Freshly removed thyroids were homogenized under denaturing
condition in solution containing 4% SDS, 2% mercaptoethanol, and 10
mM Tris, pH 6.8, and boiled for 5 min. Different aliquots
of thyroid homogenates (50 mg/ml protein) were analyzed by reducing
4 or 4.5% SDS-PAGE. Protein bands were visualized by staining with
Coomassie brilliant blue R-250. Parallel samples were also subjected to
SDS-PAGE and transferred to nitrocellulose before examination for
intact Tg by immunoblotting with antirat Tg and antimouse Tg antibodies
(4, 20) and secondary antibody conjugated with horseradish peroxidase.
ECL chemiluminescence method (Amersham Pharmacia Biotech,
Arlington Heights, IL) was used for the band detection.
Determination of the Tg cDNA Sequence
The sequences of 5'- and 3'-ends of the Tg cDNA were
determined by sequencing the cDNA clones obtained from the cDNA
libraries of the F344 and WIC-rdw rat thyroids. The two cDNA
libraries were generated using a ZAP-cDNA Gigapack Gold Cloning Kit
(Stratagene, La Jolla, CA) according to the
manufacturer’s instruction. The clones were screened by the
plaque-hybridization method with probes of 5'- and 3'-end fragments of
the rat Tg cDNA, of 967 and 930 bp in size, respectively.
The rest of the Tg cDNA sequence was determined by
sequencing TA clones containing the rat Tg cDNA fragments,
which had been amplified by RT-PCR with the primers shown in Table 1.
Primers were synthesized according to the sequences of the murine and
human Tg cDNAs. TA cloning was performed using a TA Cloning
Kit (Invitrogen, Carlsbad, CA) in accordance with the
manufacturer’s instructions. Sequencing was performed with a
DSQ-1000 automatic sequencer (Shimazu, Kyoto, Japan) using a
primer cycle sequencing kit (Amersham Pharmacia Biotech, Buckinghamshire, UK) according to the manufacturer’s
instructions.
Detection of the rdw Mutation by
Restriction Enzyme Digestion
RT-PCR was performed with total RNAs extracted from thyroids as
templates and sense (5'-CAACACCTCCTCAAATCAGT-3', nt 6,815–6,835) and
antisense (5'-GTCCAGTAGCCCCCAGTTGC-3', nt 7,055–7,075) primers. PCR
products were digested by incubation with 1 U of NiaIV
(New England Biolabs, Inc., Beverly, MA) at 37 C for
16 h and electrophoresed in 6% polyacrylamide gels containing 90
mM Tris-borate and 2 mM
EDTA. DNA bands were visualized by staining with 0.5 µg/ml ethidium
bromide solution.
Site-Directed Mutagenesis
QuickChange site-directed mutagenesis kit
(Stratagene, La Jolla, CA) was used to make the G to C
point mutation in the full-length normal mouse Tg cDNA (20)
in pBK-CMV vector (Stratagene) according to the
manufacturer’s instruction. The two primers T1–5'-GCT GAC CAT TGA TCG
CTC CAT CCT GGC-3' and T2–5'-GCC AGG ATG GAG CGA TCA ATG GTC AGC-3',
both containing the desired mutation and each complementary to the
opposite strands of the vector, were used in a PCR reaction. Four
Tg cDNAs were isolated and sequenced to determine the
presence of the point mutation. The presence of the rdw
mutation, G6958C, in the new Tg cDNA was confirmed by a
second sequencing.
Transient Transfections of COS-7 Cells
COS-7 cell were grown in DMEM containing 10% FBS to
approximately 70–80% confluency before transfection with 1 µg of
each plasmid identified as pBK-CMV-normal Tg,
pBK-CMV-cog Tg, or pBK-CMV-rdw Tg using
Lipofectamine reagent (Life Technologies, Inc.) in
serum-free DMEM, according to the instructions. After 5 h
incubation, the transfection mixture was washed and replaced with fresh
DMEM containing 10% FBS for an additional 48 h. The cells were
then chased overnight in serum-free DMEM and lysed in denaturing buffer
containing 4% SDS. The secreted medium collected during chase was
precipitated with 10% TCA on ice for 1 h before centrifugation at
14,000 x g for 10 min at 4 C. After washing with 100%
ethanol, the obtained pellet was resuspended in denaturing cell lysis
buffer. Both the cell lysates and the secreted media were subjected to
reducing 4% SDS-PAGE before the Western blot analysis using anti-Tg
antibody.
|
ACKNOWLEDGMENTS |
|---|
Parts of this work were supported by NIH Grant DK-52076 (P.S.K.) and Veterans Affairs Merit Award (P.S.K.).
|
FOOTNOTES |
|---|
1 These authors contributed equally. 
Received for publication July 21, 2000. Revision received September 12, 2000. Accepted for publication September 13, 2000.
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONRESULTSDISCUSSIONMATERIALS AND METHODSREFERENCES |
|---|
This article has been cited by other articles:
 |
|
 |
|
  D.-M. Niu, J.-H. Hsu, K.-W. Chong, C.-H. Huang, Y.-H. Lu, C.-H. Kao, H.-C. Yu, M.-Y. Lo, and T.-S. Jap Six New Mutations of the Thyroglobulin Gene Discovered in Taiwanese Children Presenting with Thyroid Dyshormonogenesis J. Clin. Endocrinol. Metab., December 1, 2009; 94(12): 5045 - 5052. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Lee, X. Wang, B. Di Jeso, and P. Arvan The Cholinesterase-like Domain, Essential in Thyroglobulin Trafficking for Thyroid Hormone Synthesis, Is Required for Protein Dimerization J. Biol. Chem., May 8, 2009; 284(19): 12752 - 12761. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. S. Wagner, S. M. Wajner, and A. L. Maia The role of thyroid hormone in testicular development and function J. Endocrinol., December 1, 2008; 199(3): 351 - 365. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Caputo, C. M Rivolta, V. J Gutnisky, L. Gruneiro-Papendieck, A. Chiesa, G. Medeiros-Neto, R. Gonzalez-Sarmiento, and H. M Targovnik Recurrence of the p.R277X/p.R1511X compound heterozygous mutation in the thyroglobulin gene in unrelated families with congenital goiter and hypothyroidism: haplotype analysis using intragenic thyroglobulin polymorphisms J. Endocrinol., October 1, 2007; 195(1): 167 - 177. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Menon, J. Lee, W. A. Abplanalp, S.-E. Yoo, T. Agui, S.-i. Furudate, P. S. Kim, and P. Arvan Oxidoreductase Interactions Include a Role for ERp72 Engagement with Mutant Thyroglobulin from the rdw/rdw Rat Dwarf J. Biol. Chem., March 2, 2007; 282(9): 6183 - 6191. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. M. Rivolta, C. M. Moya, V. J. Gutnisky, V. Varela, J. M. Miralles-Garcia, R. Gonzalez-Sarmiento, and H. M. Targovnik A New Case of Congenital Goiter with Hypothyroidism Caused by a Homozygous p.R277X Mutation in the Exon 7 of the Thyroglobulin Gene: A Mutational Hot Spot Could Explain the Recurrence of This Mutation J. Clin. Endocrinol. Metab., June 1, 2005; 90(6): 3766 - 3770. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. J. Gutnisky, C. M. Moya, C. M. Rivolta, S. Domene, V. Varela, J. V. Toniolo, G. Medeiros-Neto, and H. M. Targovnik Two Distinct Compound Heterozygous Constellations (R277X/IVS34-1G>C and R277X/R1511X) in the Thyroglobulin (TG) Gene in Affected Individuals of a Brazilian Kindred with Congenital Goiter and Defective TG Synthesis J. Clin. Endocrinol. Metab., February 1, 2004; 89(2): 646 - 657. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Lisi, A. Pinchera, R. T. McCluskey, T. E. Willnow, S. Refetoff, C. Marcocci, P. Vitti, F. Menconi, L. Grasso, F. Luchetti, et al. Preferential megalin-mediated transcytosis of low-hormonogenic thyroglobulin: A control mechanism for thyroid hormone release PNAS, December 9, 2003; 100(25): 14858 - 14863. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Kopp Perspective: Genetic Defects in the Etiology of Congenital Hypothyroidism Endocrinology, June 1, 2002; 143(6): 2019 - 2024. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Leonardi, P. Vito, C. Mauro, F. Pacifico, L. Ulianich, E. Consiglio, S. Formisano, and B. Di Jeso Endoplasmic Reticulum Stress Causes Thyroglobulin Retention in this Organelle and Triggers Activation of Nuclear Factor-{kappa}B Via Tumor Necrosis Factor Receptor-Associated Factor 2 Endocrinology, June 1, 2002; 143(6): 2169 - 2177. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Marino, L. Chiovato, S. Lisi, A. Pinchera, and R. T. McCluskey Binding of the Low Density Lipoprotein Receptor-Associated Protein (RAP) to Thyroglobulin (Tg): Putative Role of RAP in the Tg Secretory Pathway Mol. Endocrinol., October 1, 2001; 15(10): 1829 - 1837. [Abstract] [Full Text] [PDF]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Endocrinology | Endocrine Reviews | J. Clin. End. & Metab. |
| Molecular Endocrinology | Recent Prog. Horm. Res. | All Endocrine Journals |
