Lack of In Vivo Functional Compensation Between Pax Family Groups II and III in Rodents

ABSTRACT The proteins encoded by the retinoblastoma gene family, pRB, p107, and p130, have been implicated in the regulation of cellular proliferation, differentiation, and transformation. Because interactions between p130 and E2F transcription factors have been proposed to play a role in the establishment and/or maintenance of quiescence in human peripheral T lymphocytes, we examined lymphoid differentiation and proliferation in p130-deficient mice. We show thatp130−/− T cells proliferate normally in culture and exhibit normal cell-mediated immune function in vivo. However, p130−/− T lymphocytes expressed elevated levels of p107, and the characteristic p130-E2F DNA binding complex was replaced by a p107-E2F complex. Adoptive transfer of fetal liver lymphoid progenitors allowed us to circumvent the neonatal lethality associated with loss of p130 and p107 and to analyze the phenotype of p130−/−;p107−/− peripheral T lymphocytes. These cells achieved a quiescent state, exhibited derepression of a subset of E2F target genes, and were hypersensitive to concanavalin A stimulation. Interestingly, a significant portion of the E2F-4 inp130−/−;p107−/− T cells was detected in a complex with pRB and an as-yet-unidentified protein. These findings provide a biochemical basis for functional compensation between pRB family proteins.

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Pax3 induces cell aggregation and regulates phenotypic mesenchymal-epithelial interconversion

Journal of Cell Science ◽

10.1242/jcs.115.3.517 ◽

2002 ◽

Vol 115 (3) ◽

pp. 517-529 ◽

Cited By ~ 2

Author(s):

O'Neil Wiggan ◽

Marc P. Fadel ◽

Paul A. Hamel

Keyword(s):

Embryonic Development ◽

Epithelial To Mesenchymal Transition ◽

Morphological Changes ◽

Cell Aggregation ◽

Structural Defects ◽

Mesenchymal Transition ◽

Mammalian Cell Lines ◽

Morphological Defects ◽

Pax Family

Paired box-containing transcription factors play fundamental roles in pattern formation during embryonic development of diverse organisms ranging from Drosophila to mammals. Although mutations to Pax3 and other Pax-family genes in both mice and humans result in numerous tissue-specific morphological defects, little is known about the cellular processes that Pax genes regulate. We show that extopic Pax3 expression in two distinct phenotypically mesenchymal mammalian cell lines induces the formation of multi-layered condensed cell aggregates with epithelial characteristics. For one of these lines, we showed further that Pax3-induced cell aggregation is accompanied by specific morphological changes, including a significant reduction in cell size, altered cell shape and dramatic alterations to both membrane and cytoskeleton architecture. In addition to mediating a phenotypic mesenchymal-to-epithelial transition, Pax3 also establishes the conditions in these cells for a subsequent hepatocyte growth factor/scatter factor(HGF/SF)-induced phenotypic epithelial-to-mesenchymal transition. Thus, our data show a novel morphogenetic activity for Pax3 which, when absent in vivo,is predicted to give rise to the observed structural defects in somites and the neural tube during embryonic development.

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Involvement of pax2 in ovarian development and recrudescence of catfish: a role in steroidogenesis

Journal of Endocrinology ◽

10.1530/joe-16-0103 ◽

2016 ◽

Vol 231 (3) ◽

pp. 181-195 ◽

Cited By ~ 11

Author(s):

Yarikipati Prathibha ◽

Balasubramanian Senthilkumaran

Keyword(s):

Rna Silencing ◽

Ovarian Development ◽

Ovarian Follicle ◽

Wnt Signaling Pathway ◽

Steroidogenic Enzyme ◽

Pax Family ◽

Estradiol 17Β ◽

Essential Transcription Factor

PAX2, a member of paired box family, is an essential transcription factor for the organ development in vertebrates including teleosts, yet no evidence has been shown for its involvement in reproduction. To study this, partial- and/or full-length cDNA of pax2 was isolated from the ovary of catfish, Clarias batrachus, along with its other Pax family members, pax1 and pax9. Tissue distribution and ontogeny expression analysis indicated the prevalence of pax2 but not pax1 and pax9 in ovary. Varied phase-wise expression during ovarian cycle and elevation of pax2 after human chorionic gonadotropin induction showed probable regulation by gonadotropins. Pax2 could be localized in various stages of oocytes and in follicular layer of vitellogenic and post-vitellogenic oocytes. To assess the functional significance of pax2, transient RNA silencing was performed using primary catfish ovarian follicle culture, in vitro, and in catfish, in vivo, through ovary-targeted injection of PEI-esiRNA. Pax2 siRNA treatment reduced the expression of various transcripts related to ovarian development like signaling molecules such as wnt4 and wnt5, estrogen receptors, several steroidogenic enzymes and transcription factors. These transitions in transcript levels might have been mediated by Pax2 acting upstream of wnt4/5 that may play a role in steroidogenesis and/or ovarian development along with ad4bp/sf-1 or by direct or indirect interaction with steroidogenic enzyme genes, which is evident from the change in the levels of serum estradiol-17β but not 17α,20β-dihydroxy-4-pregnen-3-one. Taken together, it seems that pax2 has a plausible role during ovarian development and/or recrudescence of catfish either directly or indirectly through Wnt signaling pathway.

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Murine Coronavirus Evolution In Vivo: Functional Compensation of a Detrimental Amino Acid Substitution in the Receptor Binding Domain of the Spike Glycoprotein

Journal of Virology ◽

10.1128/jvi.79.12.7629-7640.2005 ◽

2005 ◽

Vol 79 (12) ◽

pp. 7629-7640 ◽

Cited By ~ 18

Author(s):

Sonia Navas-Martin ◽

Susan T. Hingley ◽

Susan R. Weiss

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Receptor Binding ◽

Amino Acid Substitution ◽

Binding Domain ◽

Receptor Binding Domain ◽

Spike Glycoprotein ◽

Functional Compensation

ABSTRACT Murine coronavirus A59 strain causes mild to moderate hepatitis in mice. We have previously shown that mutants of A59, unable to induce hepatitis, may be selected by persistent infection of primary glial cells in vitro. These in vitro isolated mutants encoded two amino acids substitutions in the spike (S) gene: Q159L lies in the putative receptor binding domain of S, and H716D, within the cleavage signal of S. Here, we show that hepatotropic revertant variants may be selected from these in vitro isolated mutants (Q159L-H716D) by multiple passages in the mouse liver. One of these mutants, hr2, was chosen for more in-depth study based on a more hepatovirulent phenotype. The S gene of hr2 (Q159L- R654H -H716D- E1035D ) differed from the in vitro isolates (Q159L-H716D) in only 2 amino acids (R654H and E1035D). Using targeted RNA recombination, we have constructed isogenic recombinant MHV-A59 viruses differing only in these specific amino acids in S (Q159L-R654H-H716D-E1035D). We demonstrate that specific amino acid substitutions within the spike gene of the hr2 isolate determine the ability of the virus to cause lethal hepatitis and replicate to significantly higher titers in the liver compared to wild-type A59. Our results provide compelling evidence of the ability of coronaviruses to rapidly evolve in vivo to highly virulent phenotypes by functional compensation of a detrimental amino acid substitution in the receptor binding domain of the spike glycoprotein.

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RBL1 (p107) functions as tumor suppressor in glioblastoma and small-cell pancreatic neuroendocrine carcinoma

10.1101/528299 ◽

2019 ◽

Cited By ~ 1

Author(s):

Thomas Naert ◽

Dionysia Dimitrakopoulou ◽

Dieter Tulkens ◽

Suzan Demuynck ◽

Rivka Noelanders ◽

...

Keyword(s):

Tumor Suppressor ◽

Choroid Plexus ◽

Neuroendocrine Carcinoma ◽

Choroid Plexus Papilloma ◽

Small Cell ◽

Compensatory Mechanisms ◽

P53 Expression ◽

Functional Compensation ◽

Pancreatic Neuroendocrine Carcinoma

AbstractAlterations of the retinoblastoma and/or the p53 signaling network are associated with specific cancers such as high-grade astrocytoma/glioblastoma, small cell lung cancer (SCLC), choroid plexus tumors and small-cell pancreatic neuroendocrine carcinoma (SC-PaNEC). However, the intricate functional compensation between RB1 and the related pocket proteins RBL1/p107 and RBL2/p130 in suppressing tumorigenesis remains poorly understood. Here we performed lineage-restricted parallel inactivation ofrb1andrbl1by multiplex CRISPR/Cas9 genome editing in the true diploidXenopus tropicalisto gain insight into thesein vivocompensatory mechanisms. We show that whilerb1inactivation is sufficient to induce choroid plexus papilloma, combinedrb1andrbl1inactivation is required and sufficient to drive SC-PaNEC, retinoblastoma and astrocytoma. Further, using a novel Li-Fraumeni syndrome-mimickingtp53mutantX. tropicalisline, we demonstrate increased malignancy of retinoblastoma-mutant neural malignancies upon concomitant inactivation oftp53. Interestingly, although clinical SC-PaNEC samples are characterized by abnormal p53 expression or localization, in the current experimental models, thetp53status had little effect on the establishment and growth of SC-PaNEC, but may rather be essential for maintaining chromosomal stability. SCLC was only rarely observed in our experimental set-up, indicating requirement of additional or alternative oncogenic insults. In conclusion, we used CRISPR/Cas9 to delineate the tumor suppressor properties of Rbl1 and generate new insights in functional compensation within the retinoblastoma protein family in suppressing pancreatic and specific neural cancers.

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The PAX gene egl-38 mediates developmental patterning in Caenorhabditis elegans

Development ◽

10.1242/dev.124.20.3919 ◽

1997 ◽

Vol 124 (20) ◽

pp. 3919-3928 ◽

Cited By ~ 5

Author(s):

H.M. Chamberlin ◽

R.E. Palmer ◽

A.P. Newman ◽

P.W. Sternberg ◽

D.L. Baillie ◽

...

Keyword(s):

Transcription Factors ◽

Genetic Analysis ◽

Molecular Genetic ◽

Egg Laying ◽

Paired Domain ◽

C Elegans ◽

Developmental Patterning ◽

Pax Family ◽

Insight Into

Mutations in the C. elegans gene egl-38 result in a discrete set of defects in developmental pattern formation. In the developing egg-laying system of egl-38 mutant hermaphrodites, the identity of four uterine cells is disrupted and they adopt the fate of their neighbor cells. Likewise, the identity of two rectal epithelial cells in the male tail is disrupted and one of these cells adopts the fate of its neighbor cell. Genetic analysis suggests that the egl-38 functions in the tail and the egg-laying system are partially separable, as different egl-38 mutations can preferentially disrupt the different functions. We have cloned egl-38 and shown that it is a member of the PAX family of genes, which encode transcription factors implicated in a variety of developmental patterning events. The predicted EGL-38 protein is most similar to the mammalian class of proteins that includes PAX2, PAX5 and PAX8. The sequence of egl-38 mutant DNA indicates that the tissue-preferential defects of egl-38 mutations result from substitutions in the DNA-binding paired domain of the EGL-38 protein. egl-38 thus provides the first molecular genetic insight into two specific patterning events that occur during C. elegans development and also provides the opportunity to investigate the in vivo functions of this class of PAX proteins with single cell resolution.

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Functional compensation between hematopoietic stem cell clones in vivo

EMBO Reports ◽

10.15252/embr.201745702 ◽

2018 ◽

Vol 19 (8) ◽

Cited By ~ 5

Author(s):

Lisa Nguyen ◽

Zheng Wang ◽

Adnan Y Chowdhury ◽

Elizabeth Chu ◽

Jiya Eerdeng ◽

...

Keyword(s):

Stem Cell ◽

Hematopoietic Stem Cell ◽

Hematopoietic Stem ◽

Functional Compensation ◽

Cell Clones

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Fine Structural Changes in the Microvasculature of the Mouse Pinna: Aging and Radiation Injury

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100050287 ◽

1974 ◽

Vol 32 ◽

pp. 54-55

Author(s):

S. Phyllis Steamer ◽

Rosemarie L. Devine

Keyword(s):

Structural Changes ◽

Radiation Treatment ◽

Arterial Stenosis ◽

Ultrastructural Changes ◽

Vascular Effects ◽

Microvascular Changes ◽

Surrounding Connective Tissue ◽

Fission Neutrons ◽

Total Body

The importance of radiation damage to the skin and its vasculature was recognized by the early radiologists. In more recent studies, vascular effects were shown to involve the endothelium as well as the surrounding connective tissue. Microvascular changes in the mouse pinna were studied in vivo and recorded photographically over a period of 12-18 months. Radiation treatment at 110 days of age was total body exposure to either 240 rad fission neutrons or 855 rad 60Co gamma rays. After in vivo observations in control and irradiated mice, animals were sacrificed for examination of changes in vascular fine structure. Vessels were selected from regions of specific interest that had been identified on photomicrographs. Prominent ultrastructural changes can be attributed to aging as well as to radiation treatment. Of principal concern were determinations of ultrastructural changes associated with venous dilatations, segmental arterial stenosis and tortuosities of both veins and arteries, effects that had been identified on the basis of light microscopic observations. Tortuosities and irregularly dilated vein segments were related to both aging and radiation changes but arterial stenosis was observed only in irradiated animals.

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Induction and Differentiation of Dental Epithelium in Vivo and in Vitro

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053425 ◽

1982 ◽

Vol 40 ◽

pp. 142-145

Author(s):

E. J. Kollar

Keyword(s):

Connective Tissue ◽

Oral Mucosa ◽

Basal Lamina ◽

Functional Derivatives ◽

Specific Source ◽

Dental Epithelium ◽

Connective Tissue Stroma

The differentiation and maintenance of many specialized epithelial structures are dependent on the underlying connective tissue stroma and on an intact basal lamina. These requirements are especially stringent in the development and maintenance of the skin and oral mucosa. The keratinization patterns of thin or thick cornified layers as well as the appearance of specialized functional derivatives such as hair and teeth can be correlated with the specific source of stroma which supports these differentiated expressions.

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Ultrastructural Correlations between Clonal Human Tumor Colonies and in Vivo Neoplasms

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053711 ◽

1982 ◽

Vol 40 ◽

pp. 210-211

Author(s):

M.J. Murphy ◽

R.R. Price ◽

J.C. Sloman

Keyword(s):

Cultured Cells ◽

Human Tumor ◽

Cell Type ◽

Tumor Mass ◽

Initial Cell ◽

Cloning Assay ◽

Human Tumor Cloning ◽

The Relationship

The in vitro human tumor cloning assay originally described by Salmon and Hamburger has been applied recently to the investigation of differential anti-tumor drug sensitivities over a broad range of human neoplasms. A major problem in the acceptance of this technique has been the question of the relationship between the cultured cells and the original patient tumor, i.e., whether the colonies that develop derive from the neoplasm or from some other cell type within the initial cell population. A study of the ultrastructural morphology of the cultured cells vs. patient tumor has therefore been undertaken to resolve this question. Direct correlation was assured by division of a common tumor mass at surgical resection, one biopsy being fixed for TEM studies, the second being rapidly transported to the laboratory for culture.

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