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Developmental Phenotype (developmental + phenotype)
Selected AbstractsDevelopmental phenotypes and reduced Wnt signaling in mice deficient for pygopus 2GENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 5 2007Boan Li Abstract Canonical Wnt signaling involves complex intracellular events culminating in the stabilization of ,-catenin, which enters the nucleus and binds to LEF/TCF transcription factors to stimulate gene expression. Pygopus was identified as a genetic modifier of Wg (Wnt homolog) signaling in Drosophila, and encodes a PHD domain protein that associates with the ,-catenin/LEF/TCF complex. Two murine pygopus paralogs, mpygo1 and mpygo2, have been identified, but their roles in development and Wnt signaling remain elusive. In this study, we report that ablation of mpygo2 expression in mice causes defects in morphogenesis of both ectodermally and endodermally derived tissues, including brain, eyes, hair follicles, and lung. However, no gross abnormality was observed in embryonic intestine. Using a BAT-gal reporter, we found Wnt signaling at most body sites to be reduced in the absence of mpygo2. Taken together, our studies show for the first time that mpygo2 deletion affects embryonic development of some but not all Wnt-requiring tissues. genesis 45:318,325, 2007. © 2007 Wiley-Liss, Inc. [source] Transcriptional regulatory cascades controlling plasma cell differentiationIMMUNOLOGICAL REVIEWS, Issue 1 2003Kuo-I Lin Summary:, Plasma cells are the terminally differentiated effector cells of the B lymphocyte lineage. Recently, studies using genetically altered mice and analyses of global gene expression programs have significantly expanded our understanding of the molecular mechanisms regulating plasmacytic differentiation. Specific molecular components of a multistep cascade of transcriptional regulators have been identified. Furthermore, two transcriptional regulators, X box binding protein-1 (XBP-1) and B lymphocyte induced maturation protein-1 (Blimp-1), have been shown to be necessary for plasmacytic differentiation. In addition to providing a mechanistic basis for the induction of genes necessary for immunoglobulin secretion, cessation of cell cycle and other phenotypic changes characteristic of terminally differentiated plasma cells, these studies have led to the important concept that plasmacytic differentiation involves repression of regulators, such as Bcl-6 and Pax5, that are necessary to maintain the earlier developmental phenotype of activated, germinal center B cells. This review describes our current understanding of the transcriptional cascades regulating terminal differentiation of B cells. [source] crinkled leaves 8 , A mutation in the large subunit of ribonucleotide reductase , leads to defects in leaf development and chloroplast division in Arabidopsis thalianaTHE PLANT JOURNAL, Issue 1 2007Sarah Garton Summary The crinkled leaves8 (cls8) mutant of Arabidopsis thaliana displays a developmental phenotype of abnormal leaf and flower morphology, reduced root growth and bleached leaf sections. Map-based cloning identified the mutation as being within the gene encoding the large subunit of ribonucleotide reductase (RNR1), the enzyme that catalyses the rate-limiting step in the production of deoxyribonucleoside triphosphates (dNTPs) for DNA synthesis and repair. Levels of dTTP and dATP were significantly reduced in cls8. Two further mutant cls8 alleles and cls8::RNAi plants show similar or more severe phenotypes. The cls8-1 mutant has fewer copies of the chloroplast genome, and fewer, larger chloroplasts than wild-type plants. The ultrastructure of the chloroplast, however, appears normal in cls8-1 leaves. We present evidence that, under conditions of limited dNTP supply, the inhibition of chloroplast DNA replication may be the primary factor in inducing aberrant growth. [source] Morphological evolution in sea urchin development: hybrids provide insights into the pace of evolutionBIOESSAYS, Issue 4 2004Maria Byrne Hybridisations between related species with divergent ontogenies can provide insights into the bases for evolutionary change in development. One example of such hybridisations involves sea urchin species that exhibit either standard larval (pluteal) stages or those that develop directly from embryo to adult without an intervening feeding larval stage. In such crosses, pluteal features were found to be restored in fertilisations of the eggs of some direct developing sea urchins (Heliocidaris erythrogramma) with the sperm of closely (Heliocidaris tuberculata) and distantly (Pseudoboletia maculata) related species with feeding larvae. Such results can be argued to support the punctuated equilibrium model,conservation in pluteal regulatory systems and a comparatively rapid switch to direct development in evolution.1,2 Generation of hybrids between distantly related direct developers may, however, indicate evolutionary convergence. The ,rescue' of pluteal features by paternal genomes may require maternal factors from H. erythrogramma because the larva of this species has pluteal features. In contrast, pluteal features were not restored in hybridisations with the eggs of Holopneustes purpurescens, which lacks pluteal features. How much of pluteal development can be lost before it cannot be rescued in such crosses? The answer awaits hybridisations among indirect and direct developing sea urchins differing in developmental phenotype, in parallel with investigations of the genetic programs involved. BioEssays 26:343,347, 2004. © 2004 Wiley Periodicals, Inc. [source] | ||||||||||