scholarly journals Temporal regulation of axonal repulsion by alternative splicing of a conserved microexon in mammalian Robo1 and Robo2

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Verity Johnson ◽  
Harald J Junge ◽  
Zhe Chen
Keyword(s):  
Alternative Splicing ◽  
Axon Guidance ◽  
Developmental Expression ◽  
Splicing Factors ◽  
Commissural Axons ◽  
Temporal Regulation ◽  
Robo Receptors ◽  
Temporal And Spatial ◽  
Cns Midline ◽  
Control Protein

Proper connectivity of the nervous system requires temporal and spatial control of axon guidance signaling. As commissural axons navigate across the CNS midline, ROBO-mediated repulsion has traditionally been thought to be repressed before crossing, and then to become upregulated after crossing. The regulation of the ROBO receptors involves multiple mechanisms that control protein expression, trafficking, and activity. Here, we report that mammalian ROBO1 and ROBO2 are not uniformly inhibited precrossing and are instead subject to additional temporal control via alternative splicing at a conserved microexon. The NOVA splicing factors regulate the developmental expression of ROBO1 and ROBO2 variants with small sequence differences and distinct guidance activities. As a result, ROBO-mediated axonal repulsion is activated early in development to prevent premature crossing and becomes inhibited later to allow crossing. Postcrossing, the ROBO1 and ROBO2 isoforms are disinhibited to prevent midline reentry and to guide postcrossing commissural axons to distinct mediolateral positions.

scholarly journals A Theoretical Model of Axon Guidance by the Robo Code

2003 ◽  
Vol 15 (3) ◽  
pp. 549-564 ◽  
Author(s):  
Geoffrey J. Goodhill
Keyword(s):  
Theoretical Model ◽  
Axon Guidance ◽  
Ectopic Expression ◽  
Lateral Position ◽  
Commissural Axons ◽  
Coding Scheme ◽  
Simple Theoretical Model ◽  
Robo Receptors ◽  
Different Populations

After crossing the midline, different populations of commissural axons in Drosophila target specific longitudinal pathways at different distances from the midline. It has recently been shown that this choice of lateral position is governed by the particular combination of Robo receptors expressed by these axons, presumably in response to a gradient of Slit released by the midline. Here we propose a simple theoretical model of this combinatorial coding scheme. The principal results of the model are that purely quantitative rather than qualitative differences between the different Robo receptors are sufficient to account for the effects observed following removal or ectopic expression of specific Robo receptors, and that the steepness of the Slit gradient in vivo must exceed a certain minimum for the results observed experimentally to be consistent.

scholarly journals The alternative splicing of the CD45 tyrosine phosphatase is controlled by negative regulatory trans-acting splicing factors.

1992 ◽  
Vol 267 (10) ◽  
pp. 7139-7147
Author(s):  
D.M. Rothstein ◽  
H Saito ◽  
M Streuli ◽  
S.F. Schlossman ◽  
C Morimoto
Keyword(s):  
Alternative Splicing ◽  
Tyrosine Phosphatase ◽  
Splicing Factors

scholarly journals Alternative splicing acts as an independent prognosticator in ovarian carcinoma

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yan Ouyang ◽  
Kaide Xia ◽  
Xue Yang ◽  
Shichao Zhang ◽  
Li Wang ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Regression Analysis ◽  
Alternative Splicing ◽  
Ovarian Carcinoma ◽  
Cancer Patients ◽  
Cox Regression ◽  
Excision Repair ◽  
Splicing Factors ◽  
Prognostic Signature ◽  
Cox Regression Analysis

AbstractAlternative splicing (AS) events associated with oncogenic processes present anomalous perturbations in many cancers, including ovarian carcinoma. There are no reliable features to predict survival outcomes for ovarian cancer patients. In this study, comprehensive profiling of AS events was conducted by integrating AS data and clinical information of ovarian serous cystadenocarcinoma (OV). Survival-related AS events were identified by Univariate Cox regression analysis. Then, least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression analysis were used to construct the prognostic signatures within each AS type. Furthermore, we established a splicing-related network to reveal the potential regulatory mechanisms between splicing factors and candidate AS events. A total of 730 AS events were identified as survival-associated splicing events, and the final prognostic signature based on all seven types of AS events could serve as an independent prognostic indicator and had powerful efficiency in distinguishing patient outcomes. In addition, survival-related AS events might be involved in tumor-related pathways including base excision repair and pyrimidine metabolism pathways, and some splicing factors might be correlated with prognosis-related AS events, including SPEN, SF3B5, RNPC3, LUC7L3, SRSF11 and PRPF38B. Our study constructs an independent prognostic signature for predicting ovarian cancer patients’ survival outcome and contributes to elucidating the underlying mechanism of AS in tumor development.

scholarly journals Splicing Genomics Events in Cervical Cancer: Insights for Phenotypic Stratification and Biomarker Potency

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 130
Author(s):  
Flavia Zita Francies ◽  
Sheynaz Bassa ◽  
Aristotelis Chatziioannou ◽  
Andreas Martin Kaufmann ◽  
Zodwa Dlamini
Keyword(s):  
Cervical Cancer ◽  
Alternative Splicing ◽  
Cancer Progression ◽  
Molecular Mechanisms ◽  
Therapy Resistance ◽  
Splicing Factors ◽  
Aberrant Splicing ◽  
Molecular Alteration ◽  
Common Cancer ◽  
Potential Biomarkers

Gynaecological cancers are attributed to the second most diagnosed cancers in women after breast cancer. On a global scale, cervical cancer is the fourth most common cancer and the most common cancer in developing countries with rapidly increasing mortality rates. Human papillomavirus (HPV) infection is a major contributor to the disease. HPV infections cause prominent cellular changes including alternative splicing to drive malignant transformation. A fundamental characteristic attributed to cancer is the dysregulation of cellular transcription. Alternative splicing is regulated by several splicing factors and molecular changes in these factors lead to cancer mechanisms such as tumour development and progression and drug resistance. The serine/arginine-rich (SR) proteins and heterogeneous ribonucleoproteins (hnRNPs) have prominent roles in modulating alternative splicing. Evidence shows molecular alteration and expression levels in these splicing factors in cervical cancer. Furthermore, aberrant splicing events in cancer-related genes lead to chemo- and radioresistance. Identifying clinically relevant modifications in alternative splicing events and splicing variants, in cervical cancer, as potential biomarkers for their role in cancer progression and therapy resistance is scrutinised. This review will focus on the molecular mechanisms underlying the aberrant splicing events in cervical cancer that may serve as potential biomarkers for diagnosis, prognosis, and novel drug targets.

scholarly journals Trans-acting Factors Required for Inclusion of Regulated Exons in the Ultrabithorax mRNAs of Drosophila melanogaster

Genetics ◽  
1999 ◽  
Vol 151 (4) ◽  
pp. 1517-1529 ◽  
Author(s):  
James M Burnette ◽  
Allyson R Hatton ◽  
A Javier Lopez
Keyword(s):  
Drosophila Melanogaster ◽  
Alternative Splicing ◽  
P Element ◽  
Splicing Factors ◽  
Loss Of Function ◽  
Large Collection ◽  
Splicing Pattern ◽  
Alternatively Spliced ◽  
Hypomorphic Alleles

Abstract Alternatively spliced Ultrabithorax mRNAs differ by the presence of internal exons mI and mII. Two approaches were used to identify trans-acting factors required for inclusion of these cassette exons. First, mutations in a set of genes implicated in the control of other alternative splicing decisions were tested for dominant effects on the Ubx alternative splicing pattern. To identify additional genes involved in regulation of Ubx splicing, a large collection of deficiencies was tested first for dominant enhancement of the haploinsufficient Ubx haltere phenotype and second for effects on the splicing pattern. Inclusion of the cassette exons in Ubx mRNAs was reduced strongly in heterozygotes for hypomorphic alleles of hrp48, which encodes a member of the hnRNP A/B family and is implicated in control of P-element splicing. Significant reductions of mI and mII inclusion were also observed in heterozygotes for loss-of-function alleles of virilizer, fl(2)d, and crooked neck. The products of virilizer and fl(2)d are also required for Sxl autoregulation at the level of splicing; crooked neck encodes a protein with structural similarities to yeast-splicing factors Prp39p and Prp42p. Deletion of at least five other loci caused significant reductions in the inclusion of mI and/or mII. Possible roles of identified factors are discussed in the context of the resplicing strategy for generation of alternative Ubx mRNAs.

scholarly journals Characterization of alternative splicing events and prognostic signatures in breast cancer

BMC Cancer ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Pihua Han ◽  
Jingjun Zhu ◽  
Guang Feng ◽  
Zizhang Wang ◽  
Yanni Ding
Keyword(s):  
Breast Cancer ◽  
Alternative Splicing ◽  
Proportional Hazards ◽  
Pearson Correlation ◽  
Original Data ◽  
Cox Proportional Hazards ◽  
Prognostic Indicators ◽  
Splicing Factors ◽  
Rna Seq

Abstract Background Breast cancer (BRCA) is one of the most common cancers worldwide. Abnormal alternative splicing (AS) frequently observed in cancers. This study aims to demonstrate AS events and signatures that might serve as prognostic indicators for BRCA. Methods Original data for all seven types of splice events were obtained from TCGA SpliceSeq database. RNA-seq and clinical data of BRCA cohorts were downloaded from TCGA database. Survival-associated AS events in BRCA were analyzed by univariate COX proportional hazards regression model. Prognostic signatures were constructed for prognosis prediction in patients with BRCA based on survival-associated AS events. Pearson correlation analysis was performed to measure the correlation between the expression of splicing factors (SFs) and the percent spliced in (PSI) values of AS events. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were conducted to demonstrate pathways in which survival-associated AS event is enriched. Results A total of 45,421 AS events in 21,232 genes were identified. Among them, 1121 AS events in 931 genes significantly correlated with survival for BRCA. The established AS prognostic signatures of seven types could accurately predict BRCA prognosis. The comprehensive AS signature could serve as independent prognostic factor for BRCA. A SF-AS regulatory network was therefore established based on the correlation between the expression levels of SFs and PSI values of AS events. Conclusions This study revealed survival-associated AS events and signatures that may help predict the survival outcomes of patients with BRCA. Additionally, the constructed SF-AS networks in BRCA can reveal the underlying regulatory mechanisms in BRCA.

scholarly journals Sim2 Mutants Have Developmental Defects Not Overlapping with Those of Sim1 Mutants

2002 ◽  
Vol 22 (12) ◽  
pp. 4147-4157 ◽  
Author(s):  
Eleni Goshu ◽  
Hui Jin ◽  
Rachel Fasnacht ◽  
Mike Sepenski ◽  
Jacques L. Michaud ◽  
...  
Keyword(s):  
Genetic Interaction ◽  
Expression Patterns ◽  
Gene Mutations ◽  
Congenital Scoliosis ◽  
Developmental Defects ◽  
Lung Inflation ◽  
Left And Right ◽  
Temporal And Spatial ◽  
Cns Midline ◽  
Midline Cells

ABSTRACT The mouse genome contains two Sim genes, Sim1 and Sim2. They are presumed to be important for central nervous system (CNS) development because they are homologous to the Drosophila single-minded (sim) gene, mutations in which cause a complete loss of CNS midline cells. In the mammalian CNS, Sim2 and Sim1 are coexpressed in the paraventricular nucleus (PVN). While Sim1 is essential for the development of the PVN (J. L. Michaud, T. Rosenquist, N. R. May, and C.-M. Fan, Genes Dev. 12:3264-3275, 1998), we report here that Sim2 mutant has a normal PVN. Analyses of the Sim1 and Sim2 compound mutants did not reveal obvious genetic interaction between them in PVN histogenesis. However, Sim2 mutant mice die within 3 days of birth due to lung atelectasis and breathing failure. We attribute the diminished efficacy of lung inflation to the compromised structural components surrounding the pleural cavity, which include rib protrusions, abnormal intercostal muscle attachments, diaphragm hypoplasia, and pleural mesothelium tearing. Although each of these structures is minimally affected, we propose that their combined effects lead to the mechanical failure of lung inflation and death. Sim2 mutants also develop congenital scoliosis, reflected by the unequal sizes of the left and right vertebrae and ribs. The temporal and spatial expression patterns of Sim2 in these skeletal elements suggest that Sim2 regulates their growth and/or integrity.

Developmental expression of mouse stromelysin-3 mRNA

Development ◽  
1995 ◽  
Vol 121 (4) ◽  
pp. 947-955 ◽  
Author(s):  
O. Lefebvre ◽  
C. Regnier ◽  
M.P. Chenard ◽  
C. Wendling ◽  
P. Chambon ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Mesenchymal Cells ◽  
Developmental Expression ◽  
Spatiotemporal Pattern ◽  
Commissural Axons ◽  
Embryonic Tissues ◽  
Trophoblastic Cells ◽  
Neuroepithelial Cells ◽  
Stromelysin 3

We have used northern blot analysis and in situ hybridization to study the spatial distribution of stromelysin-3 (ST3) expression during mouse embryogenesis. ST3 mRNA was observed in trophoblastic cells at the site of embryonic implantation (7.5-8.5 days) and in a variety of developing embryonic tissues. In these tissues, the highest ST3 expression levels were observed during the development of the external features of limb, tail and snout, and during bone and spinal cord morphogenesis. In limb, tail and snout, ST3 expression was specifically detected in mesenchymal cells lining the basement membrane at the junction of primitive dermis and epidermis, and adjacent to epithelial cells undergoing proliferation and/or apoptosis. In bone, ST3 was expressed in invasive mesenchymal cells and, in the spinal cord in neuroepithelial cells of the floor plate, at the time that this structure is crossed by commissural axons. Altogether, these observations suggest a role for ST3 during embryonic morphogenesis, in tissue remodeling processes associated with cell proliferation, death and/or invasion. Moreover, when compared to urokinase and tissue plasminogen activators, the spatiotemporal pattern of ST3 expression shows some similarities, but was not completely superimposable, suggesting that these genes may cooperate in some developing tissues and have specific functions in others.

scholarly journals Netrin-Mediated Axon Guidance to the CNS Midline Revisited

Neuron ◽  
2017 ◽  
Vol 94 (4) ◽  
pp. 691-693 ◽  
Author(s):  
Randal A. Hand ◽  
Alex L. Kolodkin
Keyword(s):  
Axon Guidance ◽  
Cns Midline
Sign in / Sign up

Export Citation Format

Share Document