Regulation of Growth and Function of Epididymides

ABSTRACT Microphthalmia transcription factor (MITF) and STAT3 are two transcription factors that play a major role in the regulation of growth and function in mast cells and melanocytes. In the present study, we explored the MITF-PIAS3-STAT3 network of interactions, how these interactions regulate gene expression, and how cytokine-mediated phosphorylation of MITF and STAT3 is involved in the in vivo interplay between these three proteins. In NIH 3T3 cells stimulated via gp130 receptor, transfected MITF was found to be phosphorylated at S409. Such phosphorylation of MITF leads to PIAS3 dissociation from MITF and its association with STAT3. Activation of mouse melanoma and mast cells through gp130 or c-Kit receptors induced the mobilization of PIAS3 from MITF to STAT3. In mast cells derived from MITF di/di mice, whose MITF lacks the Zip domain (PIAS3-binding domain), we found downregulation in mRNA levels of genes regulated by either MITF or STAT3. This regulatory mechanism is of considerable importance since it is likely to advance the deciphering of a role for MITF and STAT3 in mast cells and melanocytes.

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Hormonal Regulation of Growth and Function of Insulin-Producing Cells in Culture

Proceedings in Life Sciences - Hormonally Defined Media ◽

10.1007/978-3-642-69290-1_31 ◽

1983 ◽

pp. 264-273 ◽

Cited By ~ 2

Author(s):

J. Høiriis Nielsen

Keyword(s):

Hormonal Regulation ◽

Cells In Culture ◽

Insulin Producing Cells ◽

And Function ◽

Regulation Of Growth

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Modulating Testicular Mass in Xenografting: A Model to Explore Testis Development and Endocrine Function

Endocrinology ◽

10.1210/en.2010-0415 ◽

2010 ◽

Vol 151 (8) ◽

pp. 4018-4023 ◽

Cited By ~ 11

Author(s):

Stefan Schlatt ◽

Kathrin Gassei ◽

Birgit Westernströer ◽

Jens Ehmcke

Keyword(s):

Testicular Tissue ◽

Endocrine Function ◽

Endocrine Regulation ◽

Djungarian Hamster ◽

Hpg Axis ◽

Testicular Growth ◽

Intrinsic Mechanism ◽

And Function ◽

Regulation Of Growth ◽

Testis Tissue

The hypothalamic-pituitary-gonadal (HPG) axis is involved in both the regulation of growth of the developing testis and in controlling spermatogenic and steroidogenic activity in the adult testis. Here, we develop a novel testicular xenografting model to examine to which degree testicular growth and function are controlled by intra- and extratesticular factors. Two or eight halves of neonatal Djungarian hamster testes were implanted into intact, hemicastrated, or castrated nude mouse recipients, and the development of the grafts under reduced or increased competition of testicular tissue was monitored and analyzed. We hypothesized that the outgrowth of the testicular grafts is influenced by the total amount of testicular tissue present in a host and that less testicular tissue in a host would result in more extended outgrowth of the grafts. Our results reveal that the hypothesis is wrong, because implanted hamster testis tissue irrespectively of the grafting condition grows to a similar size revealing an intrinsic mechanism for testicular growth. In contrast, similar size of seminal vesicle as bio-indicator of androgen levels in all hosts revealed that the steroidogenic activity is independent from the mass of testicular tissue and that steroid levels are extrinsically regulated by the recipient’s HPG axis. We propose that the model of testicular xenografting provides highly valuable options to explore testicular growth and endocrine regulation of the HPG axis.

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Identifying a common molecular mechanism for inhibition of MITF and STAT3 by PIAS3

Blood ◽

10.1182/blood-2005-08-3325 ◽

2006 ◽

Vol 107 (7) ◽

pp. 2839-2845 ◽

Cited By ~ 24

Author(s):

Carmit Levy ◽

Yu-Nee Lee ◽

Hovav Nechushtan ◽

Ora Schueler-Furman ◽

Amir Sonnenblick ◽

...

Keyword(s):

Transcriptional Activity ◽

Three Dimensional ◽

Binding Motif ◽

Alpha Helices ◽

Cellular Activation ◽

Microphthalmia Transcription Factor ◽

And Function ◽

Transcription 3 ◽

Regulation Of Growth

AbstractProtein inhibitor of activated STAT3 (PIAS3) functions in vivo as a key molecule in suppressing the transcriptional activity of both microphthalmia transcription factor (MITF) and signal transducer and activator of transcription 3 (STAT3), 2 transcription factors that play a major role in the regulation of growth and function in mast cells and melanocytes. Previously, we have demonstrated binding of PIAS3 to MITF leading to the inhibition of MITF transcriptional activity. Following cellular activation, PIAS3 is released from MITF and binds to STAT3. Now we have localized a common binding motif in PIAS3 for MITF and STAT3. This motif (PIAS82-132), which contains 50 amino acids, is sufficient for the inhibition of both MITF and STAT3. Three-dimensional protein modeling demonstrated that this motif contains 2 alpha helices. Disruption of one of the helices led to the loss of PIAS3 inhibitory activity. In addition to contributing to our understanding of the mechanisms of PIAS3 activity, these results could pave the way toward the formulation of an antioncogenic agent for the inhibition of both STAT3 and MITF.

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Conformation of Ribosomes from Escherichia Coli

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051062 ◽

1974 ◽

Vol 32 ◽

pp. 210-211

Author(s):

M. Boublik ◽

W. Hellmann ◽

F. Jenkins

Keyword(s):

Binding Sites ◽

Ribosomal Proteins ◽

Fluorescent Dyes ◽

Protein Biosynthesis ◽

Three Dimensional ◽

Spatial Arrangement ◽

Dimensional Structure ◽

Complete Understanding ◽

And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

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