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.
42-640: (Redirected from Tim ) [REDACTED] Look up Tim , tim , or TIM in Wiktionary, the free dictionary. Tim or TIM may refer to: Human names [ edit ] Timothy (given name) Tim (given name) Timmy Timo Timotheus Place names [ edit ] Tim, Denmark Tim, Kursk Oblast Tim River in northeastern Ontario, Canada Arts and entertainment [ edit ] Fictional characters [ edit ] Timothy (given name) § Fictional characters
84-850: A 1979 Australian film T.I.M. (film) , a British 2023 science fiction film Tim (novel) , a 1974 novel by Colleen McCullough TIM Defender of the Earth , a 2008 young adult science fiction novel by Sam Enthoven TIM (Owarai) , a Japanese comedy unit Treasure Island Media (TIM), a gay pornographic studio The Incredible Machine (series) , a video game series Science and technology [ edit ] Biology and chemistry [ edit ] HAVCR1 (Hepatitis A virus cellular receptor 1), also known as T-cell immunoglobulin and mucin-domain 1 (TIM-1) HAVCR2 (Hepatitis A virus cellular receptor 2), also known as T-cell immunoglobulin and mucin-domain containing-3 (TIM-3) Triosephosphate isomerase TIM (psychedelics) (thioisomescaline),
126-798: A 1979 Australian film T.I.M. (film) , a British 2023 science fiction film Tim (novel) , a 1974 novel by Colleen McCullough TIM Defender of the Earth , a 2008 young adult science fiction novel by Sam Enthoven TIM (Owarai) , a Japanese comedy unit Treasure Island Media (TIM), a gay pornographic studio The Incredible Machine (series) , a video game series Science and technology [ edit ] Biology and chemistry [ edit ] HAVCR1 (Hepatitis A virus cellular receptor 1), also known as T-cell immunoglobulin and mucin-domain 1 (TIM-1) HAVCR2 (Hepatitis A virus cellular receptor 2), also known as T-cell immunoglobulin and mucin-domain containing-3 (TIM-3) Triosephosphate isomerase TIM (psychedelics) (thioisomescaline),
168-428: A Mexican national television network Thermal interface material , any material inserted between two parts to enhance the thermal coupling between Telecom Italia Mobile , an Italian telecommunications subsidiary owned by Telecom Italia TIM Brasil , a Brazilian telecommunications subsidiary owned by Telecom Italia TIM Hellas , a Greek telecommunications subsidiary owned by Telecom Italia TIM San Marino ,
210-428: A Mexican national television network Thermal interface material , any material inserted between two parts to enhance the thermal coupling between Telecom Italia Mobile , an Italian telecommunications subsidiary owned by Telecom Italia TIM Brasil , a Brazilian telecommunications subsidiary owned by Telecom Italia TIM Hellas , a Greek telecommunications subsidiary owned by Telecom Italia TIM San Marino ,
252-424: A San Marino telecommunications subsidiary owned by Telecom Italia TIMvision , an Italian video on demand service owned by Telecom Italia IBM Tivoli Identity Manager , an identity-management system product TNO intestinal model , model systems mimicking the digestive tract Other uses [ edit ] East Timor , UNDP country code TIM TIM (Bulgaria) , an organized crime syndicate incorporated as
294-424: A San Marino telecommunications subsidiary owned by Telecom Italia TIMvision , an Italian video on demand service owned by Telecom Italia IBM Tivoli Identity Manager , an identity-management system product TNO intestinal model , model systems mimicking the digestive tract Other uses [ edit ] East Timor , UNDP country code TIM TIM (Bulgaria) , an organized crime syndicate incorporated as
336-585: A delay in TIM accumulation, which creates a phase delay. When light inputs are received in the late subjective night, a light pulse causes TIM degradation to occur earlier than under normal conditions, leading to a phase advance. In Drosophila , the negative regulator PER, from the PER/TIM complex, is eventually degraded by a casein kinase -mediated phosphorylation cycle, allowing fluctuations in gene expression according to environmental cues. These proteins mediate
378-695: A different gene function than in Drosophila . This suggests a divergence between mammalian clocks and the Drosophila clock. Moreover, mammalian tim is more orthologous to the Tim-2 ( Timeout ) paralog of the Drosophila Timeless gene than the actual gene itself. Like tim-2 , the mammalian orthologs has a C-terminal PARP1 -binding (PAB) domain. The complex they from promotes homologous recombination DNA repair. The timeless protein
420-572: A heterodimer that exhibits circadian rhythms in wild type Drosophila . Researchers in Rosbash's lab also showed that tim mRNA levels and TIM protein levels have circadian rhythms that are similar to those of the period ( per ) mRNA and its product. Experiments done jointly by the Weitz, Young, and Sehgal labs using yeast 2-hybrid proved that TIM directly binds with PER. During the early evening, PER and TIM dimerize and accumulate. Late at night,
462-548: A holding company Tim (inhabited locality) , several inhabited localities in Russia Tim ( Oldenburg Baby ), an aborted child that survived Tiako I Madagasikara , a Malagasy political party TIM, a nickname for the UK speaking clock telephone service See also [ edit ] Timothy (disambiguation) Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with
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#1732773004221504-441: A holding company Tim (inhabited locality) , several inhabited localities in Russia Tim ( Oldenburg Baby ), an aborted child that survived Tiako I Madagasikara , a Malagasy political party TIM, a nickname for the UK speaking clock telephone service See also [ edit ] Timothy (disambiguation) Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with
546-717: A list of characters named Tim Tim, a character from the film Robots Tim the Enchanter, a character from Monty Python and the Holy Grail Tim the Bear, a character from The Cleveland Show Tim the Beaver, the mascot of the Massachusetts Institute of Technology TIM, a computer from The Tomorrow People Tim, a character from The Magic School Bus Tim, the title character from
588-417: A list of characters named Tim Tim, a character from the film Robots Tim the Enchanter, a character from Monty Python and the Holy Grail Tim the Bear, a character from The Cleveland Show Tim the Beaver, the mascot of the Massachusetts Institute of Technology TIM, a computer from The Tomorrow People Tim, a character from The Magic School Bus Tim, the title character from
630-452: A series of psychedelic drugs Translocase of the inner membrane , a complex of proteins found in the inner mitochondrial membrane of the mitochondria Timeless (gene) , a gene involved in the fly circadian clock TIM barrel , a protein fold structure Transmembrane immunoglobulin and munin domain , a family of immunomodulatory proteins Other uses in science and technology [ edit ] Televisión Independiente de México ,
672-452: A series of psychedelic drugs Translocase of the inner membrane , a complex of proteins found in the inner mitochondrial membrane of the mitochondria Timeless (gene) , a gene involved in the fly circadian clock TIM barrel , a protein fold structure Transmembrane immunoglobulin and munin domain , a family of immunomodulatory proteins Other uses in science and technology [ edit ] Televisión Independiente de México ,
714-562: A similar role to orthologs in C. elegans and types of yeast, which are known to play important roles in the cell cycle . Their experiments suggested that hTIM plays an integral role in the G2/M and intra-S cell cycle checkpoints. With respect to the G2/M checkpoint, hTIM binds to the ATRIP subunit on ATR – a protein kinase sensitive to DNA damage. This binding between hTIM and ATR then leads to
756-490: Is activated by blue light, which binds to TIM and tags it for degradation. This ends the PER/TIM repression of the CLK/CYC-mediated transcription of per and tim genes, allowing per and tim mRNA to be produced to restart the cycle. This mechanism allows entrainment of flies to environmental light cues. When Drosophila receive light inputs in the early subjective night, light-induced TIM degradation causes
798-516: Is also a region of unknown function near the N-terminus of the TIM protein that contains a 32 amino acid sequence that, when deleted, causes arrhythmic behavior in the fly. In various species of Drosophila, such as D. virilis and D. melanogaster , the initiating methionine for translation of the timeless gene into TIM is in different places, with the D. virilis start site downstream of the start site in D. melanogaster . The timeless gene
840-430: Is an essential component of the molecular circadian clock in Drosophila . It acts as part of an autoregulatory feedback loop in conjunction with the period (per) gene product as noted in collaborative studies performed by the labs of Michael W. Young and Amita Sehgal. Further studies by the labs of Young, Sehgal, Charles Weitz , and Michael Rosbash indicated that timeless protein (TIM) and period protein (PER) form
882-440: Is indicative of the gene's possible association with cancer. A single nucleotide polymorphism substitution that results in the transformation of glutamine to arginine in the amino acid sequence in the human timeless gene shows no association with either morningness or eveningness tendencies in humans. This is consistent with other research, suggesting that htim is not important in the circadian rhythm of humans. Timeless
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#1732773004221924-601: Is now frequently found to be overexpressed in many different tumor types. In a study that used Timeless-targeting siRNA oligos, followed by a whole-genome expression microarray as well as network analysis. Further testing of Timeless down-regulation on cell proliferation rates of a cervical and breast cancer cell line. It was found that elevated expression of Timeless was significantly associated with more advanced tumor stage and poorer breast cancer prognosis. Similarity in gene expression signatures has allowed for TIMELESS to be identified as Kinase Suppressor of Ras -1 (KSR1)-like and
966-487: Is thought to directly connect the cell cycle with the circadian rhythm in mammals. In this model. referred to as a “direct coupling,” the two cycles share a key protein whose expression exhibits a circadian pattern. The essential role of Tim in Drosophila in creating circadian rhythm is accomplished by Cry in mammals. In mammals, Cry and Per transcription is activated by the CLOCK / BMAL1 complex, and repressed by
1008-485: The PER/CRY complex. The human timeless protein (hTIM) has been shown to be required for the production of electrical oscillations output by the suprachiasmatic nucleus (SCN), the major clock governing all tissue-specific circadian rhythms of the body. This protein also interacts with the products of major clock genes CLOCK , BMAL , PER1 , PER2 and PER3 . Sancar and colleagues investigated whether hTIM played
1050-592: The adult animated sitcom The Life & Times of Tim Tim, a character from BrainPop Mountain Tim, a supporting character in Steel Ball Run , a story arc of the Japanese manga series Jojo's Bizarre Adventure Other uses in arts and entertainment [ edit ] Tim (Avicii album) , a 2019 album by Avicii Tim (The Replacements album) , a 1985 album by The Replacements Tim (film) ,
1092-424: The adult animated sitcom The Life & Times of Tim Tim, a character from BrainPop Mountain Tim, a supporting character in Steel Ball Run , a story arc of the Japanese manga series Jojo's Bizarre Adventure Other uses in arts and entertainment [ edit ] Tim (Avicii album) , a 2019 album by Avicii Tim (The Replacements album) , a 1985 album by The Replacements Tim (film) ,
1134-401: The cricket, tim plays some role in fine-tuning of the free-running period but may not be essential for oscillation of the circadian clock. In 1998, researchers identified a mouse homolog and a human homolog of the Drosophila timeless gene. The exact role of TIM in mammals is still unclear,. Recent work on the mammalian timeless ( mTim ) in mice has suggested that the gene may not play
1176-457: The development of disease in humans. Downregulation of the timeless gene in human carcinoma cells leads to shortened telomeres , indicating its role in telomere length maintenance. Telomere-associated DNA damage also increases in timeless depleted cells, along with the delay of telomere replication. Swi1 is a timeless -related protein that is required for DNA replication in the telomere region. This association between timeless and telomeres
1218-448: The dimer travels into the nucleus to inhibit per and tim transcription. In 1996, the teams of Sehgal, Edery, and Young found that exposure to light leads to the degradation of TIM and subsequently PER. The PER/TIM heterodimer negatively regulates transcription of period ( per ) and timeless ( tim ) genes. Within this negative feedback loop, first the PER/TIM heterodimers form in the cytoplasm, accumulate, and then translocate to
1260-555: The field of chronobiology in the 1990s. The length of the coding region of the Drosophila timeless gene is 4029 base pairs, from which a 1398 amino acid protein is transcribed. The gene starts at a consensus cap site upstream of a methionine codon. It contains 11 exons and 10 introns . In various Drosophila species, the timeless protein TIM contains more highly conserved functional domains and amino acid sequence than its counterpart, PER (protein encoded by per ). CLD
1302-565: The 💕 (Redirected from Tim ) [REDACTED] Look up Tim , tim , or TIM in Wiktionary, the free dictionary. Tim or TIM may refer to: Human names [ edit ] Timothy (given name) Tim (given name) Timmy Timo Timotheus Place names [ edit ] Tim, Denmark Tim, Kursk Oblast Tim River in northeastern Ontario, Canada Arts and entertainment [ edit ] Fictional characters [ edit ] Timothy (given name) § Fictional characters
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1344-426: The lab of Michael W. Young. Unlike the Drosophila timeless gene, homologs have been discovered in other species that are non-essential for circadian rhythm. The discovery of timeless followed the discovery of the period mutants in 1971 through forward genetic screening, the cloning of per in 1984, and an experiment determining that per is circadian in 1990. This occurred during a period of rapid expansion in
1386-458: The nucleus. The complex then blocks the positive transcription factors clock (CLK) and cycle (CYC), thereby repressing the transcription of per . As part of the circadian clock, timeless is essential for entrainment to light-dark (LD) cycles. The typical period length of free-running Drosophila is 23.9 hours, requiring adaptations to the 24-hour environmental cycle. Adaptation first begins with exposure to light. This process leads to
1428-454: The oscillating expression of the transcription factor VRILLE (VRI), which is required for behavioral rhythmicity, per and tim expression, and accumulation of PDF (pigment-dispersing factor). Timeless does not appear to be essential for oscillation of the circadian clock for all insects. In wild type Gryllus bimaculatus , tim mRNA shows rhythmic expression in both LD and DD (dark-dark cycles) similar to that of per , peaking during
1470-507: The phosphorylation of Chk1 , resulting in cell cycle arrest or apoptosis. This process serves as an important control to stop the proliferation of cells with DNA damage prior to mitotic division. The role of hTIM in the intra-S checkpoint is less clear at the molecular level; however, down-regulation of hTIM leads to an increase in the rate of generation of replication forks – even in the presence of DNA damage and other regulatory responses. The Timeless gene has also been found to influence
1512-568: The rapid degradation of the TIM protein, allowing organisms to entrain at dawn to environmental cycles. In light-dark cycles, TIM protein level decreases rapidly in late night/early morning, followed by the similar but more gradual changes in PER protein level. TIM degradation is independent of per and its protein, and releases PER from the PER/TIM complex. In some cell types, the photoreceptor protein cryptochrome (CRY) physically associates with TIM and helps regulate light-dependent degradation. CRY
1554-509: The same essential role in mammals as in Drosophila as a necessary function of the circadian clock. While Tim is expressed in the Suprachiasmatic Nucleus (SCN) which is thought to be the primary oscillator in humans, its transcription does not oscillate rhythmically in constant conditions, and the TIM protein remains in the nucleus. However, mTim is shown to be necessary for embryonic development in mice, indicating
1596-439: The subjective night. When injected with tim double-stranded RNA ( dstim ), tim mRNA levels were significantly reduced and its circadian expression rhythm was eliminated. After the dstim treatment, however, adult crickets showed a clear locomotor rhythm in constant darkness, with a free-running period significantly shorter than that of control crickets injected with Discosoma sp. Red2 (DsRed2) dsRNA. These results suggest that in
1638-443: The title TIM . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=TIM&oldid=1242726067 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Tim From Misplaced Pages,
1680-457: The title TIM . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=TIM&oldid=1242726067 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Timeless (gene) In 1994, timeless
1722-416: Was discovered through forward genetic screening performed by Jeffery L. Price while working in the lab of Michael W. Young . This gene was found when they noticed an arrhythmic tim mutant via a P element screen. The tim mutation caused arrhythmic behavior, defined by the lack of ability to establish proper circadian rhythms. In 1995, the timeless gene was cloned by Amita Sehgal and partners in
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1764-467: Was the least conserved of these regions between D. virilis and D. melanogaster . These conserved parts include: the PER interaction domain, the nuclear localization signal (NLS), cytoplasmic localization domain (CLD), N-terminal end (non-functional), and C-terminal end. TIM is also known to have a basic region, which interacts with the PAS domain of the PER protein, and a central acidic region. There
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