scholarly journals Role of the Forkhead Transcription Factors Fd4 and Fd5 During Drosophila Leg Development

Author(s):  
Mireya Ruiz-Losada ◽  
Cristian Pérez-Reyes ◽  
Carlos Estella

Appendage development requires the coordinated function of signaling pathways and transcription factors to pattern the leg along the three main axes: the antero-posterior (AP), proximo-distal (PD), and dorso-ventral (DV). The Drosophila leg DV axis is organized by two morphogens, Decapentaplegic (Dpp), and Wingless (Wg), which direct dorsal and ventral cell fates, respectively. However, how these signals regulate the differential expression of its target genes is mostly unknown. In this work, we found that two members of the Drosophila forkhead family of transcription factors, Fd4 and Fd5 (also known as fd96Ca and fd96Cb), are identically expressed in the ventro-lateral domain of the leg imaginal disc in response to Dpp signaling. Here, we analyze the expression regulation and function of these genes during leg development. We have generated specific mutant alleles for each gene and a double fd4/fd5 mutant chromosome to study their function during development. We highlight the redundant role of the fd4/fd5 genes during the formation of the sex comb, a male specific structure that appears in the ventro-lateral domain of the prothoracic leg.

FACE ◽  
2021 ◽  
pp. 273250162110243
Author(s):  
Mikhail Pakvasa ◽  
Andrew B. Tucker ◽  
Timothy Shen ◽  
Tong-Chuan He ◽  
Russell R. Reid

Hedgehog signaling was discovered more than 40 years ago in experiments demonstrating that it is a fundamental mediator of limb development. Since that time, it has been shown to be important in development, homeostasis, and disease. The hedgehog pathway proceeds through a pathway highly conserved throughout animals beginning with the extracellular diffusion of hedgehog ligands, proceeding through an intracellular signaling cascade, and ending with the activation of specific target genes. A vast amount of research has been done elucidating hedgehog signaling mechanisms and regulation. This research has found a complex system of genetics and signaling that helps determine how organisms develop and function. This review provides an overview of what is known about hedgehog genetics and signaling, followed by an in-depth discussion of the role of hedgehog signaling in craniofacial development and carcinogenesis.


Development ◽  
1996 ◽  
Vol 122 (11) ◽  
pp. 3355-3362 ◽  
Author(s):  
L. Gabay ◽  
H. Scholz ◽  
M. Golembo ◽  
A. Klaes ◽  
B.Z. Shilo ◽  
...  

The induction of different cell fates along the dorsoventral axis of the Drosophila embryo requires a graded activity of the EGF receptor tyrosine kinase (DER). Here we have identified primary and secondary target genes of DER, which mediate the determination of discrete ventral cell fates. High levels of DER activation in the ventralmost cells trigger expression of the transcription factors encoded by ventral nervous system defective (vnd) and pointed P1 (pntPl). Concomitant with the induction of pntP1, high levels of DER activity lead to inactivation of the Yan protein, a transcriptional repressor of Pointed-target genes. These two antagonizing transcription factors subsequently control the expression of secondary target genes such as otd, argos and tartan. The simultaneous effects of the DER pathway on pntP1 induction and Yan inactivation may contribute to the definition of the border of the ventralmost cell fates.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10502
Author(s):  
Huan Guo ◽  
Xinke Zhao ◽  
Haixiang Su ◽  
Chengxu Ma ◽  
Kai Liu ◽  
...  

Background Radiation exposure of the thorax is associated with a greatly increased risk of cardiac morbidity and mortality even after several decades of advancement in the field. Although many studies have demonstrated the damaging influence of ionizing radiation on cardiac fibroblast (CF) structure and function, myocardial fibrosis, the molecular mechanism behind this damage is not well understood. miR-21, a small microRNA, promotes the activation of CFs, leading to cardiac fibrosis. miR-21 is overexpressed after irradiation; however, the relationship between increased miR-21 and myocardial fibrosis after irradiation is unclear. This study was conducted to investigate gene expression after radiation-induced CF damage and the role of miR-21 in this process in rats. Methods We sequenced irradiated rat CFs and performed weighted correlation network analysis (WGCNA) combined with differentially expressed gene (DEG) analysis to observe the effect on the expression profile of CF genes after radiation. Results DEG analysis showed that the degree of gene changes increased with the radiation dose. WGCNA revealed three module eigengenes (MEs) associated with 8.5-Gy-radiation—the Yellow, Brown, Blue modules. The three module eigengenes were related to apoptosis, G2/M phase, and cell death and S phase, respectively. By blocking with the cardiac fibrosis miRNA miR-21, we found that miR-21 was associated with G2/M blockade in the cell cycle and was mainly involved in regulating extracellular matrix-related genes, including Grem1, Clu, Gdf15, Ccl7, and Cxcl1. Stem-loop quantitative real-time PCR was performed to verify the expression of these genes. Five genes showed higher expression after 8.5 Gy-radiation in CFs. The target genes of miR-21 predicted online were Gdf15 and Rsad2, which showed much higher expression after treatment with antagomir-miR-21 in 8.5-Gy-irradiated CFs. Thus, miR-21 may play the role of fibrosis and G2/M blockade in regulating Grem1, Clu, Gdf15, Ccl7, Cxcl1, and Rsad2 post-irradiation.


2018 ◽  
Vol 115 (41) ◽  
pp. E9630-E9639 ◽  
Author(s):  
Virginia Andreani ◽  
Senthilkumar Ramamoorthy ◽  
Abhinav Pandey ◽  
Ekaterina Lupar ◽  
Stephen L. Nutt ◽  
...  

Plasma cell differentiation involves coordinated changes in gene expression and functional properties of B cells. Here, we study the role of Mzb1, a Grp94 cochaperone that is expressed in marginal zone (MZ) B cells and during the terminal differentiation of B cells to antibody-secreting cells. By analyzing Mzb1−/−Prdm1+/gfp mice, we find that Mzb1 is specifically required for the differentiation and function of antibody-secreting cells in a T cell-independent immune response. We find that Mzb1-deficiency mimics, in part, the phenotype of Blimp1 deficiency, including the impaired secretion of IgM and the deregulation of Blimp1 target genes. In addition, we find that Mzb1−/− plasmablasts show a reduced activation of β1-integrin, which contributes to the impaired plasmablast differentiation and migration of antibody-secreting cells to the bone marrow. Thus, Mzb1 function is required for multiple aspects of plasma cell differentiation.


2003 ◽  
Vol 31 (1) ◽  
pp. 292-297 ◽  
Author(s):  
K.U. Birkenkamp ◽  
P.J. Coffer

Recently, the FOXO (Forkhead box, class O) subfamily of Forkhead transcription factors has been identified as direct targets of phosphoinositide 3-kinase-mediated signal transduction. The AFX (acute-lymphocytic-leukaemia-1 fused gene from chromosome X), FKHR (Forkhead in rhabdomyosarcoma) and FKHR-L1 (FKHR-like 1) transcription factors are directly phosphorylated by protein kinase B, resulting in nuclear export and inhibition of transcription. This signalling pathway was first identified in the nematode worm Caenorhabditis elegans, where it has a role in regulation of the life span of the organism. Studies have shown that this evolutionarily conserved signalling module has a role in regulation of both cell-cycle progression and cell survival in higher eukaryotes. These effects are co-ordinated by FOXO-mediated induction of a variety of specific target genes that are only now beginning to be identified. Interestingly, FOXO transcription factors appear to be able to regulate transcription through both DNA-binding-dependent and -independent mechanisms. Our understanding of the regulation of FOXO activity, and defining specific transcriptional targets, may provide clues to the molecular mechanisms controlling cell fate decisions to divide, differentiate or die.


2007 ◽  
Vol 85 (1) ◽  
pp. 55-65 ◽  
Author(s):  
Josette M. Douville ◽  
Jeffrey T. Wigle

During embryonic development, the cardiovascular system first forms and then gives rise to the lymphatic vascular system. Homeobox genes are essential for both the development of the blood and lymphatic vascular systems, as well as for their maintenance in the adult. These genes all encode proteins that are transcription factors that contain a well conserved DNA binding motif, the homeodomain. It is through the homeodomain that these transcription factors bind to the promoters of target genes and regulate their expression. Although many homeodomain proteins have been found to be expressed within the vascular systems, little is known about their downstream target genes. This review highlights recent advances made in the identification of novel genes downstream of the homeodomain proteins that are necessary for regulating vascular cellular processes such as proliferation, migration, and endothelial tube formation. Factors known to regulate the functions of vascular cells via modulating the expression of homeobox genes will be discussed. We will also review current methods used to identify and characterize downstream target genes of homeodomain proteins.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Bhaskar Ponugoti ◽  
Guangyu Dong ◽  
Dana T. Graves

Diabetes is a chronic metabolic disorder, characterized by hyperglycemia resulting from insulin deficiency and/or insulin resistance. Recent evidence suggests that high levels of reactive oxygen species (ROS) and subsequent oxidative stress are key contributors in the development of diabetic complications. The FOXO family of forkhead transcription factors including FOXO1, FOXO3, FOXO4, and FOXO6 play important roles in the regulation of many cellular and biological processes and are critical regulators of cellular oxidative stress response pathways. FOXO1 transcription factors can affect a number of different tissues including liver, retina, bone, and cell types ranging from hepatocytes to microvascular endothelial cells and pericytes to osteoblasts. They are induced by oxidative stress and contribute to ROS-induced cell damage and apoptosis. In this paper, we discuss the role of FOXO transcription factors in mediating oxidative stress-induced cellular response.


Author(s):  
Brittany Cain ◽  
Brian Gebelein

Metazoans differentially express multiple Hox transcription factors to specify diverse cell fates along the developing anterior-posterior axis. Two challenges arise when trying to understand how the Hox transcription factors regulate the required target genes for morphogenesis: First, how does each Hox factor differ from one another to accurately activate and repress target genes required for the formation of distinct segment and regional identities? Second, how can a Hox factor that is broadly expressed in many tissues within a segment impact the development of specific organs by regulating target genes in a cell type-specific manner? In this review, we highlight how recent genomic, interactome, and cis-regulatory studies are providing new insights into answering these two questions. Collectively, these studies suggest that Hox factors may differentially modify the chromatin of gene targets as well as utilize numerous interactions with additional co-activators, co-repressors, and sequence-specific transcription factors to achieve accurate segment and cell type-specific transcriptional outcomes.


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