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Jc Prudhomme - One of the best experts on this subject based on the ideXlab platform.
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Structure and organization of the Bombyx mori sericin 1 gene and of the sericins 1 deduced from the sequence of the Ser 1B cDNA.
Insect Biochemistry and Molecular Biology, 1997Co-Authors: A. Garel, G. Deleage, Jc PrudhommeAbstract:The sericin 1 Primary Transcript of the silkworm Bombyx mori is differentially spliced via a tissue- and developmentally-regulated process. From a middle silk gland cDNA library, we have elucidated the sequence of one of the four mRNAs, the 4.0 kb Ser1B mRNA. Determination of alternative or constitutive exons and intron-exon boundaries allowed us to establish the nine exon-eight intron structure of the Ser1 gene. From these and previous data, it was possible to deduce the sequence of the sericins 1 and to predict the secondary structure and physiochemical properties of the different regions of the proteins.
John C. Marshall - One of the best experts on this subject based on the ideXlab platform.
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gnrh pulse frequency modulation of gonadotropin subunit gene Transcription in normal gonadotropes assessment by Primary Transcript assay provides evidence for roles of gnrh and follistatin
Endocrinology, 2002Co-Authors: Laura L. Burger, Alan C. Dalkin, Kevin W. Aylor, Daniel J. Haisenleder, John C. MarshallAbstract:We examined the time course of action of GnRH pulse frequency on gonadotropin subunit gene Transcription and assessed the roles of GnRH, follistatin (FS), and activin on differential Transcription of the LHβ and FSHβ genes. GnRH-deficient male rats were pulsed with 25 ng GnRH either every 30 min (fast frequency) or every 240 min (slow frequency) for 1–24 h. Both GnRH frequencies increased α Primary Transcript (PT) 5-fold within 6 h, but only fast frequency GnRH increased α mRNA. Only fast frequency GnRH pulses affected LHβ PT, resulting in 6- to 9-fold increases between 1–24 h. Fast frequency GnRH pulses transiently increased FSHβ PT at 1 and 6 h (4- and 2-fold, respectively); but by 24 h FSHβ PT had returned to control levels and was correlated to a 5- to 9-fold increase in FS mRNA. In contrast, slow GnRH pulses increased FSHβ PT 3- and 6-fold at 8 and 24 h, respectively, which was correlated with a decline in FS mRNA. Activin mRNA did not change significantly after either GnRH frequency, but tended to f...
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Regulation of gonadotropin subunit Transcription after ovariectomy in the rat: measurement of subunit Primary Transcripts reveals differential roles of GnRH and inhibin.
Endocrinology, 2001Co-Authors: Laura L. Burger, Alan C. Dalkin, Kevin W. Aylor, Lisa J. Workman, Daniel J. Haisenleder, John C. MarshallAbstract:The aim of this study was to determine if the changes in gonadotropin subunit gene expression following ovariectomy reflect Transcriptional and/or postTranscriptional regulation by GnRH or inhibin. Subunit Transcription rates were determined by recently developed quantitative RT-PCR for subunit Primary Transcripts (as an indicator of gene Transcription), which allow us to measure both mRNA and PT from RNA extracted from a single pituitary. Following ovariectomy, LHb PT concentrations increased 2- to 3-fold between 72 h and 7 d, paralleling changes in serum LH and LHb mRNA. In contrast, serum FSH, FSHb mRNA, and FSHb PT concentrations were 6- to 9-fold greater 12‐24 h after ovariectomy followed by an additional 2.5-fold increase at 72 h. Although a RNA was elevated at 72 h after ovariectomy, a-Primary Transcript did not change. GnRH antagonist prevented the increase in LHb-PT at 72 h, but had no effect on the increase in FSHbPT at 12 h and was only partially effective at 72 h. The acute GnRH-independent increase in FSHb-Primary Transcript after ovariectomy could be duplicated by the administration of inhibin antiserum to intact rats; inhibin-a antiserum did not affect LHbPrimary Transcript, but increased FSHb-Primary Transcript concentrations 8- to 11-fold. The half-disappearance rates of LHb and FSHb Primary Transcripts were measured after GnRH blockade or administration of recombinant human inhibin A. The half-disappearance times for LHb and FSHb Primary Transcripts following GnRH blockade were 13 and 17 min, respectively; the mRNAs did not change. The effects of inhibin were specific for FSHb; 60 min after inhibin FSHb-Primary Transcript was undetectable with a half-disappearance time of 19 min, additionally FSHb mRNA levels also fell with a half-life of 94 min. In conclusion, these data support previous evidence that GnRH regulates gonadotropin gene expression primarily at the level of Transcription. However, the acute increase in FSHb-Primary Transcript after ovariectomy or immunoneutralization of inhibin-a, and the rapid fall in FSHb-Primary Transcript following rh inhibin, provide novel evidence that inhibin suppresses FSHb gene Transcription in addition to its action in regulating FSHb mRNA stability. (Endocrinology 142: 3435‐3442, 2001)
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regulation of gonadotropin subunit gene Transcription by gonadotropin releasing hormone measurement of Primary Transcript ribonucleic acids by quantitative reverse Transcription polymerase chain reaction assays
Endocrinology, 2001Co-Authors: Alan C. Dalkin, Laura L. Burger, Kevin W. Aylor, Lisa J. Workman, Daniel J. Haisenleder, Samuel K Cho, John C. MarshallAbstract:GnRH regulates the synthesis and secretion of the pituitary gonadotropins LH and FSH. One of the actions of GnRH on the gonadotropin subunit genes (α, LHβ, and FSHβ) is the regulation of Transcription [messenger RNA (mRNA) synthesis]. Gonadotropin subunit Transcription rates increase after gonadectomy and following exogenous GnRH pulses. However, prior studies of subunit mRNA synthesis were limited by the available methodology that did not allow simultaneous measurement of gene Transcription and mature mRNA concentrations. The purpose of the current studies was to: 1) develop a reliable and sensitive method for assessing Transcription rates by measuring gonadotropin subunit Primary Transcript RNAs (PT, RNA before intron splicing); 2) investigate the PT responses to GnRH following castration or exogenous GnRH pulses; 3) characterize the half-disappearance time for the three PT species after GnRH withdrawal; and 4) correlate changes in PT concentration with steady-state gonadotropin subunit mRNA levels meas...
Victor R Ambros - One of the best experts on this subject based on the ideXlab platform.
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trans splicing of the c elegans let 7 Primary Transcript developmentally regulates let 7 microrna biogenesis and let 7 family microrna activity
Development, 2019Co-Authors: Charles Nelson, Victor R AmbrosAbstract:ABSTRACT The sequence and roles in developmental progression of the microRNA let-7 are conserved. In general, Transcription of the let-7 Primary Transcript ( pri-let- 7) occurs early in development, whereas processing of the mature let-7 microRNA arises during cellular differentiation. In Caenorhabditis elegans and other animals, the RNA-binding protein LIN-28 post-Transcriptionally inhibits let-7 biogenesis at early developmental stages, but the mechanisms by which LIN-28 does this are not fully understood. Nor is it understood how the developmental regulation of let-7 might influence the expression or activities of other microRNAs of the same seed family. Here, we show that pri-let-7 is trans-spliced to the SL1 splice leader downstream of the let-7 precursor stem-loop, which produces a short polyadenylated downstream mRNA, and that this trans-splicing event negatively impacts the biogenesis of mature let-7 microRNA in cis . Moreover, this trans-spliced mRNA contains sequences that are complementary to multiple members of the let-7 seed family ( let-7fam ) and negatively regulates let-7fam function in trans . Thus, this study provides evidence for a mechanism by which splicing of a microRNA Primary Transcript can negatively regulate said microRNA in cis as well as other microRNAs in trans .
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trans splicing of the c elegans let 7 Primary Transcript developmentally regulates let 7 microrna biogenesis and let 7 family microrna activity
bioRxiv, 2018Co-Authors: Charles Nelson, Victor R AmbrosAbstract:let-7 is a microRNA whose sequence and roles as a regulator of developmental progression are conserved throughout bilaterians. In most systems, Transcription of the let-7 locus occurs relatively early in development, whilst processing of let-7 Primary Transcript into mature microRNA arises later and is associated with cellular differentiation. In C. elegans and other animals, the RNA binding protein LIN-28 post-Transcriptionally inhibits let-7 biogenesis at early developmental stages. The mechanisms by which LIN-28 and other factors developmentally regulate let-7 biogenesis are not fully understood. Nor is it understood how the developmental regulation of let-7 might influence the expression or activities of other microRNAs of the same seed family. Here we show that in C. elegans, the Primary let-7 Transcript ( pri-let-7 ) is trans-spliced to SL1 splice leader at a position downstream of the let-7 precursor stem-loop, producing a short, polyadenylated downstream mRNA. The trans-splicing event negatively impacts the biogenesis of mature let-7 microRNA in cis , likely by destabilizing the upstream pri-let-7 fragment. Moreover, the trans-spliced downstream mRNA contains complimentary sequences to multiple members of the let-7 seed family ( let-7fam ), and thereby serves as a sponge to negatively regulate let-7fam function in trans . Thus, this study provides evidence for a mechanism by which splicing of a microRNA Primary Transcript can negatively regulate said microRNA in cis as well as other microRNAs in trans .
Marta A. Piva - One of the best experts on this subject based on the ideXlab platform.
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Ccm1p is a 15S rRNA Primary Transcript processing factor as elucidated by a novel in vivo system in Saccharomyces cerevisiae
Current Genetics, 2020Co-Authors: J. Ignacio Moreno, Ineshia S. Coleman, Classie L. Johnson, Dominique S. Green, Marta A. PivaAbstract:In Saccharomyces cerevisiae , the mitoribosomal RNA of the minor subunit, 15S rRNA, is transcribed as a bicistronic Transcript along with tRNA^W. 5′ and 3′ sequences flanking the mature Transcript must be removed by cleavage at the respective junctions before incorporating it into the mitoribosome. An in vivo dose–response triphasic system was created to elucidate the role of Ccm1p in the processing of 15S rRNA: Ccm1p supply (“On”), deprivation (“Off”), and resupply (“Back on”). After 72 h under “Off” status, the cells started to exhibit a complete mutant phenotype as assessed by their lack of growth in glycerol medium, while keeping their mitochondrial DNA integrity ( ρ ^+). Full functionality of mitochondria was reacquired upon “Back on.” 15S rRNA levels and phenotype followed the Ccm1p intramitochondrial concentrations throughout the “On–Off–Back on” course. Under “Off” status, cells gradually accumulated unprocessed 5′ and 3′ junctions, which reached significant levels at 72–96 h, probably due to a saturation of the mitochondrial degradosome (mtEXO). The Ccm1p/mtEXO mutant (Δ ccm1 /Δ dss1 ) showed a copious accumulation of 15S rRNA Primary Transcript forms, which were cleaved upon Ccm1p resupply. The gene that codes for the RNA component of RNase P was conserved in wild-type and mutant strains. Our results indicate that Ccm1p is crucial in processing the 15S rRNA Primary Transcript and does not stabilize the already mature 15S rRNA. Consequently, failure of this function in Δ ccm1 cells results, as it happens to any other unprocessed Primary Transcripts, in total degradation of 15S rRNA by mtEXO, whose mechanism of action is discussed.
A. Garel - One of the best experts on this subject based on the ideXlab platform.
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Structure and organization of the Bombyx mori sericin 1 gene and of the sericins 1 deduced from the sequence of the Ser 1B cDNA.
Insect Biochemistry and Molecular Biology, 1997Co-Authors: A. Garel, G. Deleage, Jc PrudhommeAbstract:The sericin 1 Primary Transcript of the silkworm Bombyx mori is differentially spliced via a tissue- and developmentally-regulated process. From a middle silk gland cDNA library, we have elucidated the sequence of one of the four mRNAs, the 4.0 kb Ser1B mRNA. Determination of alternative or constitutive exons and intron-exon boundaries allowed us to establish the nine exon-eight intron structure of the Ser1 gene. From these and previous data, it was possible to deduce the sequence of the sericins 1 and to predict the secondary structure and physiochemical properties of the different regions of the proteins.