| bantam | |
|---|---|
 A secondary structure and sequence conservation diagram for Bantam microRNA. | |
| Identifiers | |
| Symbol | bantam |
| Rfam | RF00727 |
| miRBase family | MIPF0000153 |
| Other data | |
| RNA type | microRNA |
| Domain(s) | Eukaryota; |
| PDB structures | PDBe |
In molecular biology, bantam microRNA is a short RNA molecule. MicroRNAs function to regulate the expression levels of other genes by several mechanisms.
In Drosophila, bantam microRNA works in the epithelial cells where it regulates the growth of dendrites in sensory neurons. [1] The Hippo signaling pathway also tends to be directly linked with the BANTAM microRNA as it regulates it to control the functionality of cell proliferation and survival. [2] [3] Recent studies show that human miRNA are also related to this pathway. [3] Homothorax (Hth) and Teashirt (Tsh) are two DNA-binding transcription factors expressed in the Drosophila eye imaginal disc. Recent studies have shown that the Hth and Tsh which are found to be important in cell survival of the Drosophila anterior optimal disc participate in the regulation of the Bantam miRNA. [2] It is concluded that the miRNA has an important function in the central pacemaker of the Drosophila circadian rhythm clock. To be more precise Bantam miRNA has an important relation with the clock component clk, thus making it an important factor of study regarding its role in Drosophila behavior. [4]
Fragile X syndrome is implicated as being regulated by the FMRP, an RNA-binding protein. Studies on Drosophila have shown that the Bantam miRNA plays an important role in the regulation of the protein dFMRP and also genetically interacts with the protein in stem cell maintenance. [5] This suggests the possibility of a relation between the miRNA and the disease. It is also suggested that the endogenous expression of the Bantam gene in the developing eye imaginal disc contributes to controlling the level of hid-induced apoptosis, which is normally involved in reducing cell number in the pupal eye disc. [6]
Cryptochromes are a class of flavoproteins found in plants and animals that are sensitive to blue light. They are involved in the circadian rhythms and the sensing of magnetic fields in a number of species. The name cryptochrome was proposed as a portmanteau combining the chromatic nature of the photoreceptor, and the cryptogamic organisms on which many blue-light studies were carried out.
RNA-binding proteins are proteins that bind to the double or single stranded RNA in cells and participate in forming ribonucleoprotein complexes. RBPs contain various structural motifs, such as RNA recognition motif (RRM), dsRNA binding domain, zinc finger and others. They are cytoplasmic and nuclear proteins. However, since most mature RNA is exported from the nucleus relatively quickly, most RBPs in the nucleus exist as complexes of protein and pre-mRNA called heterogeneous ribonucleoprotein particles (hnRNPs). RBPs have crucial roles in various cellular processes such as: cellular function, transport and localization. They especially play a major role in post-transcriptional control of RNAs, such as: splicing, polyadenylation, mRNA stabilization, mRNA localization and translation. Eukaryotic cells express diverse RBPs with unique RNA-binding activity and protein–protein interaction. According to the Eukaryotic RBP Database (EuRBPDB), there are 2961 genes encoding RBPs in humans. During evolution, the diversity of RBPs greatly increased with the increase in the number of introns. Diversity enabled eukaryotic cells to utilize RNA exons in various arrangements, giving rise to a unique RNP (ribonucleoprotein) for each RNA. Although RBPs have a crucial role in post-transcriptional regulation in gene expression, relatively few RBPs have been studied systematically.It has now become clear that RNA–RBP interactions play important roles in many biological processes among organisms.
FMR1 is a human gene that codes for a protein called fragile X messenger ribonucleoprotein, or FMRP. This protein, most commonly found in the brain, is essential for normal cognitive development and female reproductive function. Mutations of this gene can lead to fragile X syndrome, intellectual disability, premature ovarian failure, autism, Parkinson's disease, developmental delays and other cognitive deficits. The FMR1 premutation is associated with a wide spectrum of clinical phenotypes that affect more than two million people worldwide.
CLOCK is a gene encoding a basic helix-loop-helix-PAS transcription factor that is known to affect both the persistence and period of circadian rhythms.
Timeless (tim) is a gene in multiple species but is most notable for its role in Drosophila for encoding TIM, an essential protein that regulates circadian rhythm. Timeless mRNA and protein oscillate rhythmically with time as part of a transcription-translation negative feedback loop involving the period (per) gene and its protein.
Period (per) is a gene located on the X chromosome of Drosophila melanogaster. Oscillations in levels of both per transcript and its corresponding protein PER have a period of approximately 24 hours and together play a central role in the molecular mechanism of the Drosophila biological clock driving circadian rhythms in eclosion and locomotor activity. Mutations in the per gene can shorten (perS), lengthen (perL), and even abolish (per0) the period of the circadian rhythm.
PER2 is a protein in mammals encoded by the PER2 gene. PER2 is noted for its major role in circadian rhythms.
Period circadian protein homolog 1 is a protein in humans that is encoded by the PER1 gene.
The Hippo signaling pathway, also known as the Salvador-Warts-Hippo (SWH) pathway, is a signaling pathway that controls organ size in animals through the regulation of cell proliferation and apoptosis. The pathway takes its name from one of its key signaling components—the protein kinase Hippo (Hpo). Mutations in this gene lead to tissue overgrowth, or a "hippopotamus"-like phenotype.
In molecular biology miR-132 microRNA is a short non-coding RNA molecule. MicroRNAs function to regulate the expression levels of other genes by several mechanisms, generally reducing protein levels through the cleavage of mRNAs or the repression of their translation. Several targets for miR-132 have been described, including mediators of neurological development, synaptic transmission, inflammation and angiogenesis.
In molecular biology, miR-137 is a short non-coding RNA molecule that functions to regulate the expression levels of other genes by various mechanisms. miR-137 is located on human chromosome 1p22 and has been implicated to act as a tumor suppressor in several cancer types including colorectal cancer, squamous cell carcinoma and melanoma via cell cycle control.
In molecular biology, miR-184 microRNA is a short non-coding RNA molecule. MicroRNAs (miRNAs) function as posttranscriptional regulators of expression levels of other genes by several mechanisms. Several targets for miR-184 have been described, including that of mediators of neurological development, apoptosis and it has been suggested that miR-184 plays an essential role in development.
mir-279 is a short RNA molecule found in Drosophila melanogaster that belongs to a class of molecules known as microRNAs. microRNAs are ~22nt-long non-coding RNAs that post-transcriptionally regulate the expression of genes, often by binding to the 3' untranslated region of mRNA, targeting the transcript for degradation. miR-279 has diverse tissue-specific functions in the fly, influencing developmental processes related to neurogenesis and oogenesis, as well as behavioral processes related to circadian rhythms. The varied roles of mir-279, both in the developing and adult fly, highlight the utility of microRNAs in regulating unique biological processes.
Cycle (cyc) is a gene in Drosophila melanogaster that encodes the CYCLE protein (CYC). The Cycle gene (cyc) is expressed in a variety of cell types in a circadian manner. It is involved in controlling both the sleep-wake cycle and circadian regulation of gene expression by promoting transcription in a negative feedback mechanism. The cyc gene is located on the left arm of chromosome 3 and codes for a transcription factor containing a basic helix-loop-helix (bHLH) domain and a PAS domain. The 2.17 kb cyc gene is divided into 5 coding exons totaling 1,625 base pairs which code for 413 aminos acid residues. Currently 19 alleles are known for cyc. Orthologs performing the same function in other species include ARNTL and ARNTL2.
Doubletime (DBT), also known as discs overgrown (DCO), is a gene that encodes the double-time protein in fruit flies. Michael Young and his team at Rockefeller University Rockefeller University first identified and characterized the gene in 1998.
Michael Morris Rosbash is an American geneticist and chronobiologist. Rosbash is a professor and researcher at Brandeis University and investigator at the Howard Hughes Medical Institute. Rosbash's research group cloned the Drosophila period gene in 1984 and proposed the Transcription Translation Negative Feedback Loop for circadian clocks in 1990. In 1998, they discovered the cycle gene, clock gene, and cryptochrome photoreceptor in Drosophila through the use of forward genetics, by first identifying the phenotype of a mutant and then determining the genetics behind the mutation. Rosbash was elected to the National Academy of Sciences in 2003. Along with Michael W. Young and Jeffrey C. Hall, he was awarded the 2017 Nobel Prize in Physiology or Medicine "for their discoveries of molecular mechanisms controlling the circadian rhythm".
Casein kinase I isoform epsilon or CK1ε, is an enzyme that is encoded by the CSNK1E gene in humans. It is the mammalian homolog of doubletime. CK1ε is a serine/threonine protein kinase and is very highly conserved; therefore, this kinase is very similar to other members of the casein kinase 1 family, of which there are seven mammalian isoforms. CK1ε is most similar to CK1δ in structure and function as the two enzymes maintain a high sequence similarity on their regulatory C-terminal and catalytic domains. This gene is a major component of the mammalian oscillator which controls cellular circadian rhythms. CK1ε has also been implicated in modulating various human health issues such as cancer, neurodegenerative diseases, and diabetes.
Jeffrey L. Price is an American researcher and author in the fields of circadian rhythms and molecular biology. His chronobiology work with Drosophila melanogaster has led to the discoveries of the circadian genes timeless (tim) and doubletime (dbt), and the doubletime regulators spaghetti (SPAG) and bride of doubletime (BDBT).
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.
Barry James Thompson is an Australian and British developmental biologist and cancer biologist. Thompson is known for identifying genes, proteins and mechanisms involved in epithelial polarity, morphogenesis and cell signaling via the Wnt and Hippo signaling pathways, which have key roles in human cancer.