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Vrille Gene
''Vrille'' (vri) is a bZIP transcription factor found on chromosome 2 in ''Drosophila melanogaster''. Vrille mRNA and protein product (VRI) oscillate predictably on a 24-hour timescale and interact with other circadian clock genes to regulate circadian rhythms in ''Drosophila''. It is also a regulator in embryogenesis; it is expressed in multiple cell types during multiple stages in development, coordinating embryonic dorsal/ventral polarity, wing-vein differentiation, and ensuring tracheal integrity. It is also active in the embryonic gut but the precise function there is unknown. Mutations in ''vri'' alter circadian period and cause circadian arrhythmicity and developmental defects in ''Drosophila''. Discovery Helene George and Regine Terracol discovered the first ''vrille'' alleles (''vri'' and ''vri'') in 1997 by EMS-mutagenesis assay and found their products to be transcription factors involved in embryogenesis. Justin Blau elucidated additional "vrille" implications in 199 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BZIP Domain
The Basic Leucine Zipper Domain (bZIP domain) is found in many DNA binding eukaryotic proteins. One part of the domain contains a region that mediates sequence specific DNA binding properties and the leucine zipper that is required to hold together (dimerize) two DNA binding regions. The DNA binding region comprises a number of basic amino acids such as arginine and lysine. Proteins containing this domain are transcription factors. bZIP transcription factors bZIP transcription factors are found in all eukaryotes and form one of the largest families of dimerizing TFs. An evolutionary study from 2008 revealed that 4 bZIP genes were encoded by the genome of the most recent common ancestor of all plants. Interactions between bZIP transcription factors are numerous and complex and play important roles in cancer development in epithelial tissues, steroid hormone synthesis by cells of endocrine tissues, factors affecting reproductive functions, and several other phenomena that aff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biochemical Cascade
A biochemical cascade, also known as a signaling cascade or signaling pathway, is a series of chemical reactions that occur within a biological cell when initiated by a stimulus. This stimulus, known as a first messenger, acts on a receptor that is transduced to the cell interior through second messengers which amplify the signal and transfer it to effector molecules, causing the cell to respond to the initial stimulus. Most biochemical cascades are series of events, in which one event triggers the next, in a linear fashion. At each step of the signaling cascade, various controlling factors are involved to regulate cellular actions, in order to respond effectively to cues about their changing internal and external environments. An example would be the coagulation cascade of secondary hemostasis which leads to fibrin formation, and thus, the initiation of blood coagulation. Another example, sonic hedgehog signaling pathway, is one of the key regulators of embryonic development a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doublesex
''Doublesex'' (''dsx'') is a gene that is involved in the sex determination system of many insects including the fruit fly ''Drosophila melanogaster''. Sex determination The gene is expressed in both male and female flies and is subject to alternative splicing, producing the protein isoforms ''dsxf'' in females and the longer ''dsxm'' in males. The production of ''dsxf'' is caused by the presence of the female-specific version of the ''transformer'' (''tra'') gene. In a sense, the isoform of ''dsx'' informs a cell about the organism's sex; for instance, female genitals only develop if ''dsxf'' is present. In conjunction with the gene ''fruitless'', ''dsx'' also causes differences in the brain structure and behavior of males and females. Lay summary: Although the details of sex determination differ in the various species, there is a gene related to ''dsx'' in vertebrates (DMRT1) and in nematodes ( MAB-3). All of these are transcription factor In molecular biology, a tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daphnia Magna
''Daphnia magna'' is a small planktonic crustacean (adult length 1.5–5.0 mm) that belongs to the subclass Phyllopoda. Description ''D. magna'' is a typical water flea of the genus ''Daphnia''. The females reach up to 5 mm in size, the males about 2 mm, thus they are among the largest species in the genus. The body is protected by a translucent carapace made of chitin, a transparent polysaccharide. It has a ventral opening and five pairs of thoracic limbs, used to help the filtering process. Spike rows run along the back of the carapace. The intestine is hook-shaped and has two digestive ceca. The head has two antennae and a large compound eye. Adult females can be distinguished from those of otherwise similar species such as '' D. pulex'' by the absence of a comb on the abdominal claw and the presence of two distinct combs on the abdomen. The males are smaller than the females and have larger first antennas, a diagnostic feature that distinguishes them from s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apoptosis
Apoptosis (from grc, ἀπόπτωσις, apóptōsis, 'falling off') is a form of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, DNA fragmentation, and mRNA decay. The average adult human loses between 50 and 70 billion cells each day due to apoptosis. For an average human child between eight and fourteen years old, approximately twenty to thirty billion cells die per day. In contrast to necrosis, which is a form of traumatic cell death that results from acute cellular injury, apoptosis is a highly regulated and controlled process that confers advantages during an organism's life cycle. For example, the separation of fingers and toes in a developing human embryo occurs because cells between the digits undergo apoptosis. Unlike necrosis, apoptosis produces cell fragments called apoptotic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interleukin 3
Interleukin 3 (IL-3) is a protein that in humans is encoded by the ''IL3'' gene localized on chromosome 5q31.1. Sometimes also called colony-stimulating factor, multi-CSF, mast cell growth factor, MULTI-CSF, MCGF; MGC79398, MGC79399: the protein contains 152 amino acids and its molecular weight is 17 kDa. IL-3 is produced as a monomer by activated T cells, monocytes/macrophages and stroma cells. The major function of IL-3 cytokine is to regulate the concentrations of various blood-cell types. It induces proliferation and differentiation in both early pluripotent stem cells and committed progenitors. It also has many more specific effects like the regeneration of platelets and potentially aids in early antibody isotype switching. Function Interleukin 3 is an interleukin, a type of biological signal (cytokine) that can improve the body's natural response to disease as part of the immune system. In conjunction with other β common chain cytokines GM-CSF and IL-5, IL-3 works to re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Sequence
Protein primary structure is the linear sequence of amino acids in a peptide or protein. By convention, the primary structure of a protein is reported starting from the amino-terminal (N) end to the carboxyl-terminal (C) end. Protein biosynthesis is most commonly performed by ribosomes in cells. Peptides can also be synthesized in the laboratory. Protein primary structures can be directly sequenced, or inferred from DNA sequences. Formation Biological Amino acids are polymerised via peptide bonds to form a long backbone, with the different amino acid side chains protruding along it. In biological systems, proteins are produced during translation by a cell's ribosomes. Some organisms can also make short peptides by non-ribosomal peptide synthesis, which often use amino acids other than the standard 20, and may be cyclised, modified and cross-linked. Chemical Peptides can be synthesised chemically via a range of laboratory methods. Chemical methods typically synthesise ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sequence Homology
Sequence homology is the biological homology between DNA, RNA, or protein sequences, defined in terms of shared ancestry in the evolutionary history of life. Two segments of DNA can have shared ancestry because of three phenomena: either a speciation event (orthologs), or a duplication event (paralogs), or else a horizontal (or lateral) gene transfer event (xenologs). Homology among DNA, RNA, or proteins is typically inferred from their nucleotide or amino acid sequence similarity. Significant similarity is strong evidence that two sequences are related by evolutionary changes from a common ancestral sequence. Alignments of multiple sequences are used to indicate which regions of each sequence are homologous. Identity, similarity, and conservation The term "percent homology" is often used to mean "sequence similarity”, that is the percentage of identical residues (''percent identity''), or the percentage of residues conserved with similar physicochemical properties (' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NFIL3
Nuclear factor, interleukin 3 regulated, also known as NFIL3 or E4BP4 is a protein which in humans is encoded by the ''NFIL3'' gene. Function Expression of interleukin-3 ( IL-3) is restricted to activated T cells, natural killer ( NK) cells, and mast cell lines. Transcription initiation Transcription is the process of copying a segment of DNA into RNA. The segments of DNA transcribed into RNA molecules that can encode proteins are said to produce messenger RNA (mRNA). Other segments of DNA are copied into RNA molecules called ... depends on the activating capacity of specific protein factors, such as NFIL3, that bind to regulatory regions of the gene, usually upstream of the transcription start site. References Further reading * * * * * * * * Transcription factors {{gene-9-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytoskeleton
The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is composed of similar proteins in the various organisms. It is composed of three main components, microfilaments, intermediate filaments and microtubules, and these are all capable of rapid growth or disassembly dependent on the cell's requirements. A multitude of functions can be performed by the cytoskeleton. Its primary function is to give the cell its shape and mechanical resistance to deformation, and through association with extracellular connective tissue and other cells it stabilizes entire tissues. The cytoskeleton can also contract, thereby deforming the cell and the cell's environment and allowing cells to migrate. Moreover, it is involved in many cell signaling pathways and in the uptake of extracellular material ( endocytosis), the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ommatidium
The compound eyes of arthropods like insects, crustaceans and millipedes are composed of units called ommatidia (singular: ommatidium). An ommatidium contains a cluster of photoreceptor cells surrounded by support cells and pigment cells. The outer part of the ommatidium is overlaid with a transparent cornea. Each ommatidium is innervated by one axon bundle (usually consisting of 6–9 axons, depending on the number of rhabdomeres) and provides the brain with one picture element. The brain forms an image from these independent picture elements. The number of ommatidia in the eye depends upon the type of arthropod and range from as low as 5 as in the Antarctic isopod ''Glyptonotus antarcticus'', or a handful in the primitive Zygentoma, to around 30,000 in larger Anisoptera dragonflies and some Sphingidae moths. Description Ommatidia are typically hexagonal in cross-section and approximately ten times longer than wide. The diameter is largest at the surface, tapering toward the in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precursor Cell
In cell biology, a precursor cell, also called a blast cell or simply blast, is a partially differentiated cell, usually referred to as a unipotent cell that has lost most of its stem cell properties. A precursor cell is also known as a progenitor cell but progenitor cells are multipotent. Precursor cells are known as the intermediate cell before they become differentiated after being a stem cell. Usually, a precursor cell is a stem cell with the capacity to differentiate into only one cell type. Sometimes, ''precursor cell'' is used as an alternative term for unipotent stem cells. In embryology, precursor cells are a group of cells that later differentiate into one organ. A blastoma is any cancer created by malignancies of precursor cells. Precursor cells, and progenitor cells, have many potential uses in medicine. , there is research being done to use these cells to build heart valves, blood vessels and other tissues, by using blood and muscle precursor, or progenitor c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
