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We identified 2 individuals with de novo variants in SREBF2that disrupt a conserved site 1 protease (S1P) cleavage motif required for processing SREBP2 into its mature transcription factor. These individuals exhibit complex phenotypic manifestations that partially overlap with sterol regulatory element binding proteins (SREBP) pathway-related disease phenotypes, but SREBF2-related disease has not been previously reported. Thus, we set out to assess the effects of SREBF2variants on SREBP pathway activation.

Adolescent idiopathic scoliosis (AIS), a sideways curvature of the spine, is sexually dimorphic, with increased incidence in females. A genome-wide association study identified a female-specific AIS susceptibility locus near the PAX1gene. Here, we use mouse enhancer assays, three mouse enhancer knockouts, and subsequent phenotypic analyses to characterize this region. Using mouse enhancer assays, we characterize a sequence, PEC7, which overlaps the AIS-associated variant, and find it to be active in the tail tip and intervertebral disc. Removal of PEC7 or Xe1, a known sclerotome enhancer nearby, and deletion of both sequences lead to a kinky phenotype only in the Xe1 and combined (Xe1+PEC7) knockouts, with only the latter showing a female sex dimorphic phenotype. Extensive phenotypic characterization of these mouse lines implicates several differentially expressed genes and estrogen signaling in the sex dimorphic bias. In summary, our work functionally characterizes an AIS-associated locus and dissects the mechanism for its sexual dimorphism.

Simultaneous with the rise of trade protectionism in the twenty-first century has been a resurgence in nationalist politics, most notably in the USA, the UK, and parts of the EU. These developments in international and US trade policy, including Washington’s launch of a full-fledged trade war against China in March 2018, have converged disastrously with the outbreak of the novel coronavirus in November 2019 and the onset of a worldwide pandemic. Given the status of the USA as the world’s hegemon since 1945, what is new here is the effort of the Trump administration to abdicate US leadership, jettison longstanding alliances, and turn back the clock on the country’s close integration with the world economy. Already, greatly reduced flows of goods, services, and people have translated into radically reduced global growth, widespread business disruptions, and high unemployment. Remarkably, the White House has refused to recognize the severity of the pandemic and has undermined the precautions of the US science community. We argue that these multiple shocks constitute a major critical juncture on par with what the world community faced in 1945. However, in the twenty-first century we have seen that high levels of economic uncertainty and political instability have superseded the long-held notion that international interdependence would pull the world community through tough times such as these. Could the triple whammy of a destructive trade war, deadly pandemic, and secular decline of US leadership trigger a new generation of policy innovation and institution building on par with the post-1945 era? In terms of the global trade regime, it would be difficult to imagine a buoyant recovery of the world economy in the absence of a serious reckoning with the pattern of norm erosion that we identify here.

BackgroundEarly-onset scoliosis (EOS), defined by an onset age of scoliosis less than 10 years, conveys significant health risk to affected children. Identification of the molecular aetiology underlying patients with EOS could provide valuable information for both clinical management and prenatal screening.MethodsIn this study, we consecutively recruited a cohort of 447 Chinese patients with operative EOS. We performed exome sequencing (ES) screening on these individuals and their available family members (totaling 670 subjects). Another cohort of 13 patients with idiopathic early-onset scoliosis (IEOS) from the USA who underwent ES was also recruited.ResultsAfter ES data processing and variant interpretation, we detected molecular diagnostic variants in 92 out of 447 (20.6%) Chinese patients with EOS, including 8 patients with molecular confirmation of their clinical diagnosis and 84 patients with molecular diagnoses of previously unrecognised diseases underlying scoliosis. One out of 13 patients with IEOS from the US cohort was molecularly diagnosed. The age at presentation, the number of organ systems involved and the Cobb angle were the three top features predictive of a molecular diagnosis.ConclusionES enabled the molecular diagnosis/classification of patients with EOS. Specific clinical features/feature pairs are able to indicate the likelihood of gaining a molecular diagnosis through ES.

IntroductionAdolescent idiopathic scoliosis (AIS) is a common musculoskeletal disorder with strong evidence for a genetic contribution. CNVs play an important role in congenital scoliosis, but their role in idiopathic scoliosis has been largely unexplored.MethodsExome sequence data from 1197 AIS cases and 1664 in-house controls was analysed using coverage data to identify rare CNVs. CNV calls were filtered to include only highly confident CNVs with >10 average reads per region and mean log-ratio of coverage consistent with single-copy duplication or deletion. The frequency of 55 common recurrent CNVs was determined and correlated with clinical characteristics.ResultsDistal chromosome 16p11.2 microduplications containing the gene SH2B1were found in 0.7% of AIS cases (8/1197). We replicated this finding in two additional AIS cohorts (8/1097 and 2/433), resulting in 0.7% (18/2727) of all AIS cases harbouring a chromosome 16p11.2 microduplication, compared with 0.06% of local controls (1/1664) and 0.04% of published controls (8/19584) (p=2.28×10−11, OR=16.15). Furthermore, examination of electronic health records of 92 455 patients from the Geisinger health system showed scoliosis in 30% (20/66) patients with chromosome 16p11.2 microduplications containing SH2B1compared with 7.6% (10/132) of controls (p=5.6×10−4, OR=3.9).ConclusionsRecurrent distal chromosome 16p11.2 duplications explain nearly 1% of AIS. Distal chromosome 16p11.2 duplications may contribute to scoliosis pathogenesis by directly impairing growth or by altering expression of nearby genes, such as TBX6. Individuals with distal chromosome 16p11.2 microduplications should be screened for scoliosis to facilitate early treatment.

To ensure efficient genome duplication, cells have evolved numerous factors that promote unperturbed DNA replication and protect, repair and restart damaged forks. Here we identify downstream neighbor of SON (DONSON) as a novel fork protection factor and report biallelic DONSON mutations in 29 individuals with microcephalic dwarfism. We demonstrate that DONSON is a replisome component that stabilizes forks during genome replication. Loss of DONSON leads to severe replication-associated DNA damage arising from nucleolytic cleavage of stalled replication forks. Furthermore, ATM- and Rad3-related (ATR)-dependent signaling in response to replication stress is impaired in DONSON-deficient cells, resulting in decreased checkpoint activity and the potentiation of chromosomal instability. Hypomorphic mutations in DONSON substantially reduce DONSON protein levels and impair fork stability in cells from patients, consistent with defective DNA replication underlying the disease phenotype. In summary, we have identified mutations in DONSON as a common cause of microcephalic dwarfism and established DONSON as a critical replication fork protein required for mammalian DNA replication and genome stability.

To test for rare genetic mutations, a cohort of patients with unexplained early-onset scoliosis (EOS) was screened using high-density microarray genotyping. A cohort of patients with adolescent idiopathic scoliosis (AIS) was similarly screened and the results were compared.

Study Design: To test for rare genetic mutations, a cohort of patients with unexplained early-onset scoliosis (EOS) was screened using high-density microarray genotyping. A cohort of patients with adolescent idiopathic scoliosis (AIS) was similarly screened and the results were compared. Summary of Background Data: Patients with scoliosis in infancy or early childhood (EOS) are at high risk for progressive deformity and associated problems including respiratory compromise. Early-onset scoliosis is frequently associated with genetic disorders but many patients present with nonspecific clinical features and without an associated diagnosis. The authors hypothesized that EOS in these patients may be caused by rare genetic mutations detectable by next-generation genomic methods. Methods: The researchers identified 24 patients with unexplained EOS from pediatric orthopedic clinics. They genotyped them, along with 39 connecting family members, using the Illumina OmniExpress-12, version 1.0 beadchip. Resulting genotypes were analyzed for chro¬mosomal changes, specifically copy number variation and absence of heterozygosity. They screened 482 adolescent idiopathic scoliosis (AIS) patients and 744 healthy controls, who were similarly genotyped with the same beadchip, for chromosomal changes identified in the EOS cohort. Results: Copy number variation and absence of heterozygosity analyses revealed a genetic diagnosis of chromosome 15q24 microdeletion syndrome in 1 patient and maternal uniparental disomy of chromosome 14 in a second one. Prior genetic testing and clinical evaluations had been negative in both cases. A large novel chromosome 10 deletion was likely causal in a third EOS patient. These mutations identified in the EOS patients were absent in AIS patients and controls, and thus were not associated with AIS or found in asymptomatic individuals. Conclusions: These data underscore the usefulness of updated genetic evaluations including high-density microarray-based genotyping and other next-generation methods in patients with unexplained EOS, even when prior genetic studies were negative. These data also suggest the intriguing possibility that other mutations detectable by whole genome sequencing, as well as epigenetic effects, await dis¬covery in the EOS population.

BACKGROUND Pyogenic sterile arthritis, pyoderma gangrenosum, and acne (PAPA) syndrome (OMIM 604416) is a rare autosomal dominant inherited autoinflammatory syndrome characterized by pyogenic sterile arthritis and less frequently accompanied by pyoderma gangrenosum and acne. It is associated with dominant missense mutations in the proline-serine-threonine phosphatase–interacting protein 1 gene (PSTPIP1) located on chromosome 15. The patient was diagnosed as having features of a PAPA-like syndrome in which cutaneous manifestations, such as pyoderma gangrenosum and acne fulminans, predominated. OBSERVATIONS Sequencing of the PSTPIP1 gene was performed in the patient and his extended family. The patient's DNA analysis revealed a homozygous nucleotide exchange c.773G>C in the PSTPIP1 gene, leading to the substitution of glycine 258 by alanine (p.Gly258Ala), a previously reported heterozygous polymorphism. Heterozygous changes were identified in both of the patient's parents and in 7 other family members, all of whom were asymptomatic. The patient was treated with canakinumab, a human anti–interleukin 1β monoclonal antibody, which led to rapid remission of the symptoms. CONCLUSIONS To our knowledge, this is the first reported case of the resolution of dermatological symptoms associated with a PAPA-like syndrome using canakinumab treatment. Further study of the p.Gly258Ala variant is warranted to determine whether this mutation has a role in causing an apparently recessive cutaneous syndrome resembling PAPA syndrome.

PAPA syndrome (Pyogenic Arthritis, Pyoderma gangrenosum, and Acne) is an autosomal dominant, hereditary auto-inflammatory disease arising from mutations in the PSTPIP1/CD2BP1 gene on chromosome 15q. These mutations produce a hyper-phosphorylated PSTPIP1 protein and alter its participation in activation of the “inflammasome” involved in interleukin-1 (IL-1) production. Overproduction of IL-1 is a clear molecular feature of PAPA syndrome. Ongoing research is implicating other biochemical pathways that may be relevant to the distinct pyogenic inflammation of the skin and joints characteristic of this disease. This review summarizes the recent and rapidly accumulating knowledge on these molecular aspects of PAPA syndrome and related disorders.

Adolescent idiopathic scoliosis AIS is the most common spinal deformity in children. Studies have shown low melatonin levels resulting from pinealectomy in chickens and mice result in the development scoliosis, whereas supplementation with melatonin after the pinealectomy prevented it. The mere characterization of low melatonin levels is not sufficient to explain the development of idiopathic scoliosis in primates and humans, but we hypothesize that a mutation in melatonin-related receptors may be involved with the development of scoliosis.

Clubfoot is a common birth defect that affects 135,000 newborns each year worldwide. It is characterized by equinus deformity of one or both feet and hypoplastic calf muscles. Despite numerous study approaches, the causes remains poorly understood although a multifactorial etiology is generally accepted. We considered the HOXAand HOXDgene clusters and insulinlike growth factor binding protein 3 IGFBP3 as candidate genes because of their important roles in limb and muscle morphogenesis. Twenty SNPs from the HOXAand HOXDgene clusters and 12 SNPs in IGFBP3were genotyped in a sample composed of nonHispanic white and Hispanic multiplex and simplex families discovery samples and a second sample of nonHispanic white simplex trios validation sample. Four SNPs rs6668, rs2428431, rs3801776, and rs3779456 in the HOXAcluster demonstrated altered transmission in the discovery sample, but only rs3801776, located in the HOXAbasal promoter region, showed altered transmission in both the discovery and validation samples P  0.004 and 0.028. Interestingly, HOXA9is expressed in muscle during development. An SNP in IGFBP3, rs13223993, also showed altered transmission P  0.003 in the discovery sample. Gene–gene interactions were identified between variants in HOXA, HOXD, and IGFBP3and with previously associated SNPs in mitochondrialmediated apoptotic genes. The most significant interactions were found between CASP3SNPS and variants in HOXA, HOXD, and IGFBP3. These results suggest a biologic model for clubfoot in which perturbation of HOXand apoptotic genes together affect muscle and limb development, which may cause the downstream failure of limb rotation into a plantar grade position. © 2009 WileyLiss, Inc.

Idiopathic scoliosis (AIS) is the most common pediatric spinal deformity, affecting ∼3 of children worldwide. AIS significantly impacts national health in the U. S. alone, creating disfigurement and disability for over 10 of patients and costing billions of dollars annually for treatment. Despite many investigations, the underlying etiology of IS is poorly understood. Twin studies and observations of familial aggregation reveal significant genetic contributions to IS. Several features of the disease including potentially strong genetic effects, the early onset of disease, and standardized diagnostic criteria make IS ideal for genomic approaches to finding risk factors. Here we comprehensively review the genetic contributions to IS and compare those findings to other well-described complex diseases such as Crohns disease, type 1 diabetes, psoriasis, and rheumatoid arthritis. We also summarize candidate gene studies and evaluate them in the context of possible disease aetiology. Finally, we provide study designs that apply emerging genomic technologies to this disease. Existing genetic data provide testable hypotheses regarding IS etiology, and also provide proof of principle for applying high-density genome-wide methods to finding susceptibility genes and disease modifiers.

Idiopathic talipes equinovarus (ITEV), or isolated clubfoot, is a common developmental anomaly that is characterized by a rigid foot, adducted forefoot, cavus midfoot, equinovarus of the hindfoot, and hypoplastic calf musculature. The etiology of this common birth defect is largely unknown, but genetic factors have been implicated in population and family studies and maternal smoking during pregnancy has been identified as an environmental risk factor. The biotransformation of exogenous substances, such as tobacco smoke, is modulated by numerous genes including N‐acetylation genes, NAT1 and NAT2. Functional variants of these genes exist and can be distinguished by genotyping. We hypothesized that variation in NAT1 and NAT2 genes might be associated with ITEV. To test this hypothesis, NAT1 and NAT2 were genotyped in a sample of 56 multiplex ITEV families, 57 trios with a positive family history and 160 simplex trios with ITEV. The results detected a slight decrease in the expected number of homozygotes for the NAT2 normal allele in the Hispanic simplex trios. In addition, in a pilot case–control study of ITEV, there were significantly more slow NAT2 acetylators among the cases. This suggests that slow acetylation may be a risk factor for ITEV. This study is the first to find evidence suggesting a role for a biotransformation candidate gene in the etiology of ITEV and provides a scientific foundation to further explore the contributions of other tobacco metabolism genes in the etiology of clubfoot. © 2007 Wiley‐Liss, Inc.

Far from serving as an inert skeletal scaffold, bone is a dynamic tissue that cycles through tightly coordinated cycles of developmental growth and regeneration. Bone growth, which determines the overall growth of vertebrates, is well-characterized histologically and increasingly understood at the molecular level. Positional cloning strategies applied to diseases of simple Mendelian inheritance have revealed genes important in the proper formation of bone. Functional studies of these genes, aided considerably by insights provided by studies of orthologs in various model systems, have led to significant advances in our understanding of the pathways of mammalian bone morphogenesis. One such disorder, hereditary multiple exostoses, is caused by members of the EXT tumor suppressor gene family. Progress on the molecular dissection of this disorder, with emphasis on the interplay of genomic, model system, and clinical studies, is reviewed herein. We are now challenged to re-direct the biochemical pathway of chondrogenesis/osteogenesis defined by the EXT genes toward therapeutic control of bone growth and malignancy.

Far from serving as an inert skeletal scaffold, bone is a dynamic tissue that cycles through tightly coordinated cycles of developmental growth and regeneration. Bone growth, which determines the overall growth of vertebrates, is well-characterized histologically and increasingly understood at the molecular level. In recent years traditional positional cloning applied to diseases of simple Mendelian inheritance have revealed genes important in the proper formation of bone. Functional studies of these genes, aided considerably by insights provided by studies of homologous genes in animal models and other organisms, have led to significant advances in our understanding of the pathways of mammalian bone morphogenesis. One such disorder, hereditary multiple exostoses, is caused by members of the EXT tumor suppressor gene family. Progress in the molecular dissection of this disorder, with emphasis on important genomic techniques and strategies, is reviewed herein. We are now challenged to reconstruct the biochemical pathway of chondrogenesis / osteogenesis defined by the EXT genes as a step toward therapeutic control of bone growth and malignancy.

Genome-wide linkage surveys in large multiplex families with apparent inherited idiopathic scoliosis.

To localize the gene for familial recurrent arthritis via a genome-wide linkage scan in an extended kindred with the disease. A 3-generation family in which 9 members were diagnosed with juvenile idiopathic arthritis (JIA) was ascertained. In this family the disease was of very early onset and included episodic inflammation leading to eventual destruction of joints, muscle, and skin. We treated this disorder as a distinct clinical entity that we have named “familial recurrent arthritis.” A genome-wide linkage scan with polymorphic microsatellites at 10–15-cM resolution was initiated. The genome-wide scan generated a maximum 2-point logarithm of odds score with D15S211 (Zmax = 3.27 at θmax= 0.0010). Haplotype reconstruction defined a candidate region of ~20 cM flanked proximally by D15S983 and distally by D15S127 on human chromosome 15. A gene for familial recurrent arthritis was localized to 15q22-24, as a result of a genome-wide linkage scan in a large, multiply affected kindred. Identification of the altered gene will provide insights into the pathogenesis of autoimmune joint destruction that is reminiscent of JIA.

Embryonic formation and patterning of the vertebrate spinal column requires coordination of many molecular cues. After birth, the integrity of the spine is impacted by developmental abnormalities of the skeletal, muscular and nervous systems, which may result in deformities, such as kyphosis and scoliosis. We sought to identify novel genetic mouse models of severe spine deformity by implementing in vivo skeletal radiography as part of a high-throughput saturation mutagenesis screen. We report selected examples of genetic mouse models following radiographic screening of 54,497 mice from 1275 pedigrees. An estimated 30.44% of autosomal genes harbored predicted damaging alleles examined twice or more in the homozygous state. Of the 1275 pedigrees screened, 7.4% presented with severe spine deformity developing in multiple mice, and of these, meiotic mapping implicated N-ethyl-N-nitrosourea alleles in 21% of pedigrees. Our study provides proof of concept that saturation mutagenesis is capable of discovering novel mouse models of human disease, including conditions with skeletal, neural and neuromuscular pathologies. Furthermore, we report a mouse model of skeletal disease, including severe spine deformity, caused by recessive mutation in Scube3. By integrating results with a human clinical exome database, we identified a patient with undiagnosed skeletal disease who harbored recessive mutations in SCUBE3, and we demonstrated that disease-associated mutations are associated with reduced transactivation of Smad signaling in vitro. All radiographic results and mouse models are made publicly available through the Mutagenetix online database with the goal of advancing understanding of spine development and discovering novel mouse models of human disease.

We have constructed a 3.1 megabase (Mb) physical map of chromosome 17p11.2–p12, which contains a submicroscopic duplication in patients with Charcot–Marie–Tooth disease type 1A (CMT1A). We find that the CMT1A duplication is a tandem repeat of 1.5 Mb of DNA. A YAC contig encompassing the CMT1A duplication and spanning the endpoints was also developed. Several low copy repeats in 17p11.2–p12 were identified including the large (> 17 kb) CMT1A–REP unit which may be part of a mosaic repeat. CMT1A–REP flanks the 1.5 Mb CMT1A monomer unit on normal chromosome 17 and is present in an additional copy on the CMT1A duplicated chromosome. We propose that the de novo CMT1A duplication arises from unequal crossing over due to misalignment at these CMT1A–REP repeat sequences during meiosis.

Charcot-Marie-Tooth disease type 1A (CMT1A) is the most common inherited peripheral neuropathy in humans, characterized electrophysiologically by decreased nerve conduction velocities (NCVs). CMT1A is associated with a large submicroscopic DNA duplication in proximal 17p. In this report we demonstrate that a patient with a cytogenetically visible duplication, dup(17)(p11.2p12), has decreased NCV. Molecular analysis demonstrated this patient was duplicated for all the DNA markers duplicated in CMT1A as well as markers both proximal and distal to the CMT1A duplication. These data support the hypothesis that the CMT1A phenotype can result from a gene dosage effect.

The human chromosome 5q31-q33 region contains an interesting cluster of growth factor and receptor genes. In addition, several genetic disease loci have been localized within this region, but have not as yet been isolated as molecular clones. These include those loci involved in autosomal dominant limb-girdle muscular dystrophy, diastrophic dysplasia. Treacher Collins syndrome, and myeloid disorders associated with the 5q- syndrome. A yeast artificial chromosome (YAC) contig of this region would assist in the further localization and isolation of these genes. We have used YACs isolated from the Washington University and Centre d'Etude du Polymorphisme Humain YAC libraries, including YACs from the large insert (mega) YAC library to build a contig greater than 3 Mb in size. An STS content strategy coupled with limited walking from YAC ends was used to isolate 22 overlapping YACs with as much as sixfold coverage. A total of 20 STSs, derived from genes, anonymous sequences, and vector Alu-PCR or inverse PCR products, were used to compile this contig. The order of loci, centromere-GRL-D5S207-D5S70-D5S545-D5S546-D5S547-D5S68-D5S548-D5S210-D5S549-D5S686-ADRB2-D5S559-CSF1R-D5S551-RPS14-D5S519-SPARC-telomere, was derived from the overlapping clones. This contig and clones derived from it will be useful substrates in selecting candidate cDNAs for the disease loci in this interval. Copyright 1994, 1999 Academic Press

The human spinal column is a dynamic, segmented, bony, and cartilaginous structure that protects the neurologic system and simultaneously provides balance and flexibility. Children with developmental disorders that affect the patterning or shape of the spine can be at risk of neurologic and other physiologic dysfunctions. The most common developmental disorder of the spine is scoliosis, a lateral deformity in the shape of the spinal column. Scoliosis may be part of the clinical spectrum that is observed in many developmental disorders, but typically presents as an isolated symptom in otherwise healthy adolescent children. Adolescent idiopathic scoliosis (AIS) has defied understanding in part due to its genetic complexity. Breakthroughs have come from recent genome-wide association studies (GWAS) and next generation sequencing (NGS) of human AIS cohorts, as well as investigations of animal models. These studies have identified genetic associations with determinants of cartilage biogenesis and development of the intervertebral disc (IVD). Current evidence suggests that a fraction of AIS cases may arise from variation in factors involved in the structural integrity and homeostasis of the cartilaginous extracellular matrix (ECM). Here, we review the development of the spine and spinal cartilages, the composition of the cartilage ECM, the so-called “matrisome” and its functions, and the players involved in the genetic architecture of AIS. We also propose a molecular model by which the cartilage matrisome of the IVD contributes to AIS susceptibility.

Scoliosis is clinically defined as a spine deformity with lateral curvature greater than 10° and the cause of the disease is elusive. Early onset scoliosis, defined by an onset age before 10 years, conveys a substantial health risk to affected children. Although exome sequencing has emerged as a first-line diagnostic method for rare diseases, genetic testing is not routinely done for children with early onset scoliosis. We aimed to explore the diagnostic yield of exome sequencing in patients with early onset scoliosis.

Fujimori's Coup and the Breakdown of Democracy in Latin America. By Charles D. Kenney. Notre Dame: University of Notre Dame Press, 2004. 379p. $60.00 cloth, $30.00 paper.In this book on Peruvian politics, Charles Kenney leaves few stones unturned in analyzing the various factors that led to the suspension of the country's constitution and the disbanding of the legislature by President Alberto Fujimori in April 1992. While I am not entirely convinced that this particular episode in Peruvian politics warrants the book-length treatment that it has received here, Kenney has done a commendable job of locating Peru's “autogolpe” (or civilian-inflicted coup) within the broader literature on the breakdown of democratic regimes in Latin America.

We have previously described a mitochondrial activity that removes 5′ leaders from yeast mitochondrial precursor tRNAs and suggested that it is a mitochondrial RNase P. Here we demonstrate that the cleavage reaction results in a 5′ phosphate on the tRNA product and thus the activity is analogous to that of other RNase Ps. A mitochondrial gene called the tRNA synthesis locus encodes an A+U rich RNA required for this activity in vivo. Two regions of this RNA display sequence similarity to conserved sequences in bacterial RNase P RNAs. This sequence similarity coupled with the analogous activities of the enzymes has led us to conclude that the RNAs are homologous and that the tRNA synthesis locus does code for the mitochondrial RNase P RNA subunit. The smallest and most abundant transcript of the tRNA synthesis locus is 490 nucleotides long. However, during purification of the holoenzyme, RNA is degraded and pieces of the original RNA are sufficient to support RNase P activity in vitro.

Mitochondrial RNase P RNA (Rpm1r) is coded by the RPM1 gene of mitochondrial DNA in many yeasts. As aninitial step to developing a genetic approach to the structure and biogenesis of yeast mitochondrial RNase P, biollstlc transformation has been used to introduce wild type and altered RPM1 genes into strains containing no mitochondrial DNA. The introduced wild type gene does support RNase P activity demonstrating that pre-existing RNase P activityis not necessary for the biosynthesis of the enzyme. Mutations Introduced Into RPM1 in vitro result in reduced accumulation of mature tRNA and in an alteration of the processing of Rpm1r In vivo.

Comments on the economy of Argentina. Two incidents that affected the country's economy; Factor that can be attributed to the country's ability to survive crisis; Status of the country's industrial production.