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TERRA (biology)
TERRA in biology is an abbreviation for "TElomeric Repeat-containing RNA". TERRA is RNA that is transcribed from telomeres — the repeating 6-nucleotide sequences that cap the ends of chromosomes. TERRA functions with shelterin to inhibit telomere lengthening by enzyme telomerase. TERRAs are essential for telomere length and maintenance. At least four factors contribute to telomere maintenance: telomerase, shelterin, TERRA and the CST Complex. TERRA can also regulate telomere length by increasing euchromatin formation. On the other hand, nonsense-mediated decay factor enrichment at telomeres may exist to prevent TERRA inhibition of telomerase. TERRA levels vary during the cell cycle, decreasing during S phase, and increasing in the transition from G2 phase to G1 phase The G1 phase, gap 1 phase, or growth 1 phase, is the first of four phases of the cell cycle that takes place in eukaryotic cell division. In this part of interphase, the cell synthesizes mRNA and proteins in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The EMBO Journal
''The EMBO Journal'' is a semi-monthly peer-reviewed scientific journal focusing on full-length papers describing original research of general interest in molecular biology and related areas. The editor-in-chief is Facundo D. Batista (Harvard Medical School). History The journal was established in 1982 and was published by Nature Publishing Group on behalf of the European Molecular Biology Organization until the launch of EMBO Press in 2013. Abstracting and indexing The journal is abstracted and indexed in: According to the ''Journal Citation Reports'', the journal has a 2021 impact factor of 13.783. See also *''EMBO Reports'' *''Molecular Systems Biology ''Molecular Systems Biology'' is a peer-reviewed open-access scientific journal covering systems biology at the molecular level (examples include: genomics, proteomics, metabolomics, microbial systems, the integration of cell signaling and r ...'' References External links * * (1986–2003 issues from microfilm) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Journal Of Biological Sciences
The ''International Journal of Biological Sciences'' is a Peer review, peer-reviewed open access scientific journal published by Ivyspring International Publisher. It publishes original articles, reviews, and short research communications in all areas of biology, biological sciences. Articles are archived in PubMed Central. The editor-in-chief is Chuxia Deng (National Institutes of Health). Abstracting and indexing The journal is abstracted and indexed in MEDLINE/PubMed, Science Citation Index Expanded, Current Contents/Life Sciences, Current Contents/Clinical Medicine, Biological Abstracts, BIOSIS Previews, The Zoological Record, EMBASE, Chemical Abstracts Service, Chemical Abstracts, CAB International, and Scopus. According to the ''Journal Citation Reports'', the journal has a 2016 impact factor of 3.873. References External links * Biology journals Open access journals Publications established in 2005 English-language journals Ivyspring International Publisher jou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Biology
Molecular biology is the branch of biology that seeks to understand the molecular basis of biological activity in and between cells, including biomolecular synthesis, modification, mechanisms, and interactions. The study of chemical and physical structure of biological macromolecules is known as molecular biology. Molecular biology was first described as an approach focused on the underpinnings of biological phenomena - uncovering the structures of biological molecules as well as their interactions, and how these interactions explain observations of classical biology. In 1945 the term molecular biology was used by physicist William Astbury. In 1953 Francis Crick, James Watson, Rosalind Franklin, and colleagues, working at Medical Research Council unit, Cavendish laboratory, Cambridge (now the MRC Laboratory of Molecular Biology), made a double helix model of DNA which changed the entire research scenario. They proposed the DNA structure based on previous research done by Ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosomes
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are the histones. These proteins, aided by chaperone proteins, bind to and condense the DNA molecule to maintain its integrity. These chromosomes display a complex three-dimensional structure, which plays a significant role in transcriptional regulation. Chromosomes are normally visible under a light microscope only during the metaphase of cell division (where all chromosomes are aligned in the center of the cell in their condensed form). Before this happens, each chromosome is duplicated (S phase), and both copies are joined by a centromere, resulting either in an X-shaped structure (pictured above), if the centromere is located equatorially, or a two-arm structure, if the centromere is located distally. The joined copies are now called sis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
G1 Phase
The G1 phase, gap 1 phase, or growth 1 phase, is the first of four phases of the cell cycle that takes place in eukaryotic cell division. In this part of interphase, the cell synthesizes mRNA and proteins in preparation for subsequent steps leading to mitosis. G1 phase ends when the cell moves into the S phase of interphase. Around 30 to 40 percent of cell cycle time is spent in the G1 phase. Overview G1 phase together with the S phase and G2 phase comprise the long growth period of the cell cycle cell division called interphase that takes place before cell division in mitosis (M phase). During G1 phase, the cell grows in size and synthesizes mRNA and protein that are required for DNA synthesis. Once the required proteins and growth are complete, the cell enters the next phase of the cell cycle, S phase. The duration of each phase, including the G1 phase, is different in many different types of cells. In human somatic cells, the cell cycle lasts about 10 hours, and the G1 H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
G2 Phase
G2 phase, Gap 2 phase, or Growth 2 phase, is the third subphase of interphase in the cell cycle directly preceding mitosis. It follows the successful completion of S phase, during which the cell’s DNA is replicated. G2 phase ends with the onset of prophase, the first phase of mitosis in which the cell’s chromatin condenses into chromosomes. G2 phase is a period of rapid cell growth and protein synthesis during which the cell prepares itself for mitosis. Curiously, G2 phase is not a necessary part of the cell cycle, as some cell types (particularly young ''Xenopus'' embryos and some cancers)) proceed directly from DNA replication to mitosis. Though much is known about the genetic network which regulates G2 phase and subsequent entry into mitosis, there is still much to be discovered concerning its significance and regulation, particularly in regards to cancer. One hypothesis is that the growth in G2 phase is regulated as a method of cell size control. Fission yeast (''Schi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S Phase
S phase (Synthesis Phase) is the phase of the cell cycle in which DNA is replicated, occurring between G1 phase and G2 phase. Since accurate duplication of the genome is critical to successful cell division, the processes that occur during S-phase are tightly regulated and widely conserved. Regulation Entry into S-phase is controlled by the G1 restriction point (R), which commits cells to the remainder of the cell-cycle if there is adequate nutrients and growth signaling. This transition is essentially irreversible; after passing the restriction point, the cell will progress through S-phase even if environmental conditions become unfavorable. Accordingly, entry into S-phase is controlled by molecular pathways that facilitate a rapid, unidirectional shift in cell state. In yeast, for instance, cell growth induces accumulation of Cln3 cyclin, which complexes with the cyclin dependent kinase CDK2. The Cln3-CDK2 complex promotes transcription of S-phase genes by inactivating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Cycle
The cell cycle, or cell-division cycle, is the series of events that take place in a cell that cause it to divide into two daughter cells. These events include the duplication of its DNA (DNA replication) and some of its organelles, and subsequently the partitioning of its cytoplasm, chromosomes and other components into two daughter cells in a process called cell division. In cells with nuclei ( eukaryotes, i.e., animal, plant, fungal, and protist cells), the cell cycle is divided into two main stages: interphase and the mitotic (M) phase (including mitosis and cytokinesis). During interphase, the cell grows, accumulating nutrients needed for mitosis, and replicates its DNA and some of its organelles. During the mitotic phase, the replicated chromosomes, organelles, and cytoplasm separate into two new daughter cells. To ensure the proper replication of cellular components and division, there are control mechanisms known as cell cycle checkpoints after each of the key steps ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nonsense-mediated Decay
Nonsense-mediated mRNA decay (NMD) is a surveillance pathway that exists in all eukaryotes. Its main function is to reduce errors in gene expression by eliminating mRNA transcripts that contain premature stop codons. Translation of these aberrant mRNAs could, in some cases, lead to deleterious gain-of-function or dominant-negative activity of the resulting proteins. NMD was first described in human cells and in yeast almost simultaneously in 1979. This suggested broad phylogenetic conservation and an important biological role of this intriguing mechanism. NMD was discovered when it was realized that cells often contain unexpectedly low concentrations of mRNAs that are transcribed from alleles carrying nonsense mutations. Nonsense mutations code for a premature stop codon which causes the protein to be shortened. The truncated protein may or may not be functional, depending on the severity of what is not translated. In human genetics, NMD has the possibility to not only limit the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euchromatin
Euchromatin (also called "open chromatin") is a lightly packed form of chromatin ( DNA, RNA, and protein) that is enriched in genes, and is often (but not always) under active transcription. Euchromatin stands in contrast to heterochromatin, which is tightly packed and less accessible for transcription. 92% of the human genome is euchromatic. In eukaryotes, euchromatin comprises the most active portion of the genome within the cell nucleus. In prokaryotes, euchromatin is the ''only'' form of chromatin present; this indicates that the heterochromatin structure evolved later along with the nucleus, possibly as a mechanism to handle increasing genome size. Structure Euchromatin is composed of repeating subunits known as nucleosomes, reminiscent of an unfolded set of beads on a string, that are approximately 11 nm in diameter. At the core of these nucleosomes are a set of four histone protein pairs: H3, H4, H2A, and H2B. Each core histone protein possesses a 'tail' str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transcription (genetics)
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 non-coding RNAs (ncRNAs). mRNA comprises only 1–3% of total RNA samples. Less than 2% of the human genome can be transcribed into mRNA ( Human genome#Coding vs. noncoding DNA), while at least 80% of mammalian genomic DNA can be actively transcribed (in one or more types of cells), with the majority of this 80% considered to be ncRNA. Both DNA and RNA are nucleic acids, which use base pairs of nucleotides as a complementary language. During transcription, a DNA sequence is read by an RNA polymerase, which produces a complementary, antiparallel RNA strand called a primary transcript. Transcription proceeds in the following general steps: # RNA polymerase, together with one or more general transcription factors, binds to promoter DNA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Cell
''Molecular Cell'' is a peer-reviewed scientific journal that covers research on cell biology at the molecular level, with an emphasis on new mechanistic insights. It was established in 1997 and is published two times per month. Its 2021 impact factor is 19.328. ''Molecular Cell'' is a Cell Press journal (an imprint of Elsevier) and is a companion to ''Cell Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery ...''. Launched in December 1997, ''Molecular Cell'' publishes a relatively small number of papers, up to 15 articles per issue. Coverage includes structure to human diseases, concentrating on molecular analyses. Topics include gene expression, RNA processing, replication, recombination and repair, structure, chaperones, receptors, signal transduction, cell cycle, metabolism, and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
