scholarly journals Developmental Expression of Latent Transforming Growth Factor β Binding Protein 2 and Its Requirement Early in Mouse Development

2000 ◽  
Vol 20 (13) ◽  
pp. 4879-4887 ◽  
Author(s):  
J. Michael Shipley ◽  
Robert P. Mecham ◽  
Erika Maus ◽  
Jeffrey Bonadio ◽  
Joel Rosenbloom ◽  
...  

ABSTRACT Latent transforming growth factor β (TGF-β) binding protein 2 (LTBP-2) is an integral component of elastin-containing microfibrils. We studied the expression of LTBP-2 in the developing mouse and rat by in situ hybridization, using tropoelastin expression as a marker of tissues participating in elastic fiber formation. LTBP-2 colocalized with tropoelastin within the perichondrium, lung, dermis, large arterial vessels, epicardium, pericardium, and heart valves at various stages of rodent embryonic development. Both LTBP-2 and tropoelastin expression were seen throughout the lung parenchyma and within the cortex of the spleen in the young adult mouse. In the testes, LTBP-2 expression was seen within lumenal cells of the epididymis in the absence of tropoelastin. Collectively, these results imply that LTBP-2 plays a structural role within elastic fibers in most cases. To investigate its importance in development, mice with a targeted disruption of the Ltbp2 gene were generated.Ltbp2 −/− mice die between embryonic day 3.5 (E3.5) and E6.5. LTBP-2 expression was not detected by in situ hybridization in E6.5 embryos but was detected in E3.5 blastocysts by reverse transcription-PCR. These results are not consistent with the phenotypes of TGF-β knockout mice or mice with knockouts of other elastic fiber proteins, implying that LTBP-2 performs a yet undiscovered function in early development, perhaps in implantation.

Breast Cancer ◽  
2011 ◽  
Vol 19 (1) ◽  
pp. 46-53 ◽  
Author(s):  
Yuko Takahashi ◽  
Hiroko Kuwabara ◽  
Masahiko Yoneda ◽  
Zenzo Isogai ◽  
Nobuhiko Tanigawa ◽  
...  

1988 ◽  
Vol 66 (8) ◽  
pp. 1113-1121 ◽  
Author(s):  
V. K. M. Han ◽  
A. J. D'Ercole ◽  
D. C. Lee

Transforming growth factors (TGFs) are polypeptides that are produced by transformed and tumour cells, and that can confer phenotypic properties associated with transformation on normal cells in culture. One of these growth-regulating molecules, transforming growth factor alpha (TGF-α), is a 50 amino acid polypeptide that is related to epidermal growth factor (EGF) and binds to the EGF receptor. Previous studies have shown that TGF-α is expressed during rodent embryogenesis between 7 and 14 days gestation. To investigate the cellular sites of TGF-α mRNA expression during development, we have performed Northern analyses and in situ hybridization histochemistry on the conceptus and maternal tissues at various gestational ages. Contrary to previous reports, both Northern analyses and in situ hybridization histochemistry indicate that TGF-α mRNA is predominantly expressed in the maternal decidua and not in the embryo. Decidual expression is induced following implantation, peaks at day 8, and declines through day 15 when the decidua is being resorbed. In situ hybridization revealed that expression of TGF-α mRNA is highest in the region of decidua adjacent to the embryo and is low or nondetectable in the uterus, placenta, and embryo. In addition, we could not detect TGF-α mRNA expression in other maternal tissues, indicating that the induction of TGF-α transcripts in the decidua is tissue specific, and not a pleiotropic response to changes in hormonal milieu that occur during pregnancy. The developmentally regulated expression of TGF-α mRNA in the decidua, together with the presence of EGF receptors in this tissue, suggests that this peptide may stimulate mitosis and angiogenesis locally by an autocrine mechanism. Because EGF receptors are also present in the embryo and placenta, TGF-α may act on these tissues by a paracrine or endocrine mechanism.


Blood ◽  
1990 ◽  
Vol 76 (10) ◽  
pp. 1946-1955 ◽  
Author(s):  
RA Fava ◽  
TT Casey ◽  
J Wilcox ◽  
RW Pelton ◽  
HL Moses ◽  
...  

We have directly demonstrated that megakaryocytes are a major site of synthesis and storage of transforming growth factor-beta 1 (TGF/beta 1) by combined immunohistochemical, immunocytochemical, and in situ hybridization methods. The presence of TGF/beta 1 messenger RNA (mRNA) in mature megakaryocytes in adult rat spleen and bone marrow (BM) was established by in situ hybridization. Localization of TGF/beta 1 protein to intact alpha-granules of megakaryocytes, its putative storage site, was accomplished in glycol-methacrylate embedded porcine BM with an immunoperoxidase technique and light microscopy. The TGF/beta 1 was sequestered in intracytoplasmic granules in a pattern virtually identical to that of another alpha-granule marker protein, fibrinogen. This observation strongly suggests packaging of TGF/beta 1 into this organelle within megakaryocytes. That TGF/beta 1 mRNA was localized to megakaryocytes suggests that the TGF/beta 1 found in the alpha-granules in platelets originates with megakaryocyte synthesis. The alpha-granule localization of TGF/beta 1, as well as fibrinogen, was also demonstrated in isolated platelets at the ultrastructural level by electronmicroscopy (EM) and postembedding colloidal-gold immunocytochemistry, thus directly demonstrating that alpha-granules are the final storage site for TGF/beta 1 in mature platelets.


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