Genetic ablation of Saposin-D in Krabbe disease eliminates psychosine accumulation but does not significantly improve demyelination.

Krabbe disease is an inherited demyelinating disease caused by a genetic deficiency of the lysosomal enzyme galactosylceramide (GalCer) ß-galactosidase (GALC). The Twitcher (Twi) mouse is a naturally occurring, genetically and enzymatically authentic mouse model that mimics infantile-onset Krabbe disease. The major substrate for GALC is the myelin lipid GalCer. However, the pathogenesis of Krabbe disease has long been explained by the accumulation of psychosine, a lyso-derivative of GalCer. Two metabolic pathways have been proposed for the accumulation of psychosine: a synthetic pathway in which galactose is transferred to sphingosine and a degradation pathway in which GalCer is deacylated by acid ceramidase (ACDase). Saposin-D (Sap-D) is essential for the degradation of ceramide by ACDase in lysosome. In this study, we generated Twi mice with a Sap-D deficiency (Twi/Sap-D KO), which are genetically deficient in both GALC and Sap-D and found that very little psychosine accumulated in the CNS or PNS of the mouse. As expected, demyelination with the infiltration of multinucleated macrophages (globoid cells) characteristic of Krabbe disease was milder in Twi/Sap-D KO mice than in Twi mice both in the CNS and PNS during the early disease stage. However, at the later disease stage, qualitatively and quantitatively comparable demyelination occurred in Twi/Sap-D KO mice, particularly in the PNS, and the lifespans of Twi/Sap-D KO mice were even shorter than that of Twi mice. Bone marrow-derived macrophages from both Twi and Twi/Sap-D KO mice produced significant amounts of TNF-α upon exposure to GalCer and were transformed into globoid cells. These results indicate that psychosine in Krabbe disease is mainly produced via the deacylation of GalCer by ACDase. The demyelination observed in Twi/Sap-D KO mice may be mediated by a psychosine-independent, Sap-D-dependent mechanism. GalCer-induced activation of Sap-D-deficient macrophages/microglia may play an important role in the neuroinflammation and demyelination in Twi/Sap-D KO mice.

Plasma membrane proteomic changes of Arabidopsis DRP1E during cold acclimation in association with the enhancement of freezing tolerance.

The freezing tolerance of plants that live in cold regions increases after exposure to low temperature, a process termed cold acclimation (CA). During CA, restructuring of the plasma membrane (PM) is important to enhance freezing tolerance. We have previously shown that the function of DYNAMIN-RELATED PROTEIN 1 E (DRP1E), which regulates endocytosis by pinching vesicles from the PM, is associated with the enhancement of freezing tolerance during CA in Arabidopsis. DRP1E is predicted to play a role in reconstituting the PM composition during CA. In this study, to test the validity of this hypothesis, we studied the changes in PM proteome patterns induced by drp1e mutation. In a detailed physiological analysis, after 3 days of CA, only young leaves showed significantly less increase in freezing tolerance in the mutant than in the wild type (WT). Using nano-liquid chromatography-tandem mass spectrometry, 496 PM proteins were identified. Among these proteins, 81 or 71 proteins were specifically altered in the WT or the mutant, respectively, in response to CA. Principal component analysis showed that the proteomic pattern differed between the WT and the mutant upon cold acclimation (CA), suggesting that DRP1E contributes to reconstruction of the PM during CA. Cluster analysis revealed that proteins that were significantly increased in the mutant after CA were biased toward glycosylphosphatidylinositol-anchored proteins, such as fasciclin-like arabinogalactan proteins. Thus, a primary target of DRP1E-associated PM reconstruction during CA is considered to be glycosylphosphatidylinositol-anchored proteins, which may be removed from the PM by DRP1E in young leaves after 3 days of CA.

HSP90 Stabilizes Auxin-Responsive Phenotypes by Masking a Mutation in the Auxin Receptor TIR1.

Heat shock protein 90 (HSP90) is a molecular chaperone that is required for the function of various substrate proteins, also known as client proteins. It is proposed that HSP90 buffers or hides phenotypic variations in animals and plants by masking mutations in some of its client proteins. However, none of the client proteins with cryptic mutations has been identified to date. Here, we identify the first client protein example by which HSP90 buffers a mutation: the auxin receptor transport inhibitor response 1 (TIR1). TIR1 interacts with HSP90 in the nucleus. An HSP90-specific inhibitor abolished the nuclear localization of TIR1 and the auxin-induced degradation of a TIR1-substrate, indicating that TIR1 is an HSP90 client protein. Plants with a null mutation in the TIR1 gene had a defect in auxin response, whereas plants with a point mutation in the TIR1 gene responded to auxin treatment in young seedlings, but a cryptic defect in its auxin response was exposed with HSP90 inhibitor treatment. These results demonstrate that HSP90 masks a point mutation in the auxin receptor TIR1 and thereby buffers auxin-responsive phenotypes.

Joining characteristics of titanium-based orthodontic wires connected by laser and electrical welding methods.

This study investigated the possibility of electrical and laser welding to connect titanium-based alloy (beta-titanium and nickel-titanium) wires and stainless-steel or cobalt-chromium alloy wires for fabrication of combination arch-wires. Four kinds of straight orthodontic rectangular wires (0.017 × 0.025 inch) were used: stainless-steel (S-S), cobalt-chromium (Co-Cr), beta-titanium alloy (ß-Ti), and nickel-titanium (Ni-Ti). Homogeneous and heterogeneous end-to-end joints (15 mm long each) were made by electrical welding and laser welding. Non-welded wires (30 mm long) were also used as a control. Maximum loads at fracture (N) and elongation (%) were measured by conducting tensile test. The data (n = 10) were statistically analyzed using analysis of variance/Tukey test (P < 0.05).The S-S/S-S and Co-Cr/Co-Cr specimens showed significantly higher values of the maximum load (ML) at fracture and elongation (EL) than those of the Ni-Ti/Ni-Ti and ß-Ti/ß-Ti specimens for electrical welding and those of the S-S/S-S and Co-Cr/Co-Cr specimens welded by laser. On the other hand, the laser-welded Ni-Ti/Ni-Ti and ß-Ti/ß-Ti specimens exhibited higher values of the ML and EL compared to those of the corresponding specimens welded by electrical method. In the heterogeneously welded combinations, the electrically welded Ni-Ti/S-S, ß-Ti/S-S and ß-Ti/Co-Cr specimens showed significantly (P < 0.05) higher ML and EL than those of the corresponding specimens welded by laser. Electrical welding exhibited the higher values of maximum load at fracture and elongation for heterogeneously welded combinations than laser-welding.

Association between changes in 12 lifestyle behaviors and the development of metabolic syndrome during 1 year among workers in the Tokyo metropolitan area.

BACKGROUND: Practicing healthy lifestyle behaviors is a means to prevent metabolic syndrome (MetS), but the effect of changes of various behaviors over a short period is not fully understood. The purpose of this study was to elucidate the influence of changes in 12 behaviors on the development of MetS during 1 year. METHODS AND RESULTS: Of 10,442 workers who received a periodic health checkup in a health center in Tokyo in 2008, 3,137 workers aged 30-69, without MetS, who received another health checkup in 2009 were analyzed. Smoking, amounts and frequency of alcohol drinking, sleeping, exercise, walking duration and speed, late-night dinners, bedtime snacking, breakfast, eating speed, and weight control were classified into 4 groups according to change from 2008 to 2009. To examine the influence of behavioral changes on developing MetS, multiple logistic analysis was conducted after adjustment for sex, baseline age and MetS components. Changes from healthy to unhealthy behaviors in exercise, walking duration and speed, daily drinking, and weight control were significant in developing MetS compared with maintaining healthy behaviors. Those risks were higher than keeping unhealthy behaviors. Unhealthy to healthy behavior in smoking increased the risk while healthy to unhealthy behavior in eating speed decreased the risk of developing MetS. CONCLUSIONS: To prevent developing MetS during 1 year, healthy behaviors regarding physical activity, drinking, and weight management should be maintained.

Features of perceived neighborhood environment associated with daily walking time or habitual exercise: differences across gender, age, and employment status in a community-dwelling population of Japan.

OBJECTIVE: Perceived neighborhood environment (NE) is considered a determinant of daily physical activity (PA). However, evidence concerning differences among types of PA, gender, and age is limited. The study purpose was to clarify the association between NE and walking time (WT) or habitual exercise (HE) across gender, age, and employment status in a community-dwelling population of Japan. METHODS: A questionnaire mail survey with a stratified random 7,515 sampling was conducted in a northeast city in January 2007. Multiple logistic analysis was conducted to examine the associations between seven NE indices and WT or HE across gender, age, and employment status: 20-39 (young-employed), 40-59 (middle-employed), and 60-79 (old-employed or old-unemployed) after adjustment for age and means of transportation. RESULTS: A total of 3,806 residents (52.4 % females) completed the survey. Traffic and crime safety in old-unemployed males and proximity to service facilities and traffic and crime safety in middle-employed females were significantly associated with a low risk of insufficient WT. Proximity to service facilities in old-employed males, number of service facilities, places for walking, and good view in middle-employed females, and density of dwelling and proximity to service facilities in old-unemployed females were significantly associated with a low risk of non-HE. CONCLUSIONS: The association between NE and WT or HE differed across type of PA, gender, age, and employment status, and was observed mainly in middle- and old-aged females. The middle- and old-aged female residents' PA possibly were more influenced by their NE, and NE would contribute to promote active living.

[Study on pulmonary lesions in which nontuberculous mycobacteria were detected by percutaneous aspiration--a proposal to add "culture positivity of percutaneous aspiration material" to the bacteriological diagnostic criteria of pulmonary nontuberculous mycobacterial diseases].

OBJECTIVES: Culture positivity of percutaneous aspiration material" is not included in the current bacteriological criteria for diagnosis of pulmonary nontuberculous mycobacterial (NTM) diseases, which were published by the Infectious Diseases Society of America (IDSA)/American Thoracic Society (ATS) in 2007 or those released by the Japanese Society for Tuberculosis in 2008. However, percutaneous aspiration is a reliable technique for the detection of causative microorganisms isolated from the focus of infection. We discuss the benefits of including positive culture of percutaneous aspiration material in the bacteriological diagnostic criteria of pulmonary NTM diseases. METHODS: We reviewed the radiological images and clinical courses of pulmonary diseases in which NTM cultures were obtained from percutaneously aspirated materials at our hospital from 1991 to 2011. Aspiration was carried out under local anesthesia, usually with fluoroscopic guidance. After percutaneous insertion of a 22-gauge needle attached to a 20-mL syringe containing about 3 mL of saline, the lesion specimen was withdrawn together with the saline. After the needle was pulled out, the aspirated material and saline were transferred to test tubes for cytological and microbiological examinations. In patients with thin-walled cavitary lesions, saline was injected into the cavity and then aspirated. RESULTS: Percutaneous aspiration was performed in 2,742 patients and NTM disease was detected in 51 patients. Of these 51 patients, 12 had solitary nodular lesions, and in many of these patients, no NTM bacilli could be detected in the sputa or bronchial washing specimens. Mycobacterium avium was identified in 10 of the 12 cases. Four of these 10 patients were followed up after their diagnosis without any treatment: 3 showed spontaneous reduction in lesion size, while 1 patient's condition remained unchanged. Four of the remaining 6 cases were treated with anti-NTM medications, and lesion size reduced in 2 cases, while no change or deterioration was seen in the other 2. Aspiration from solitary small cavitary lesions showed a relatively high number of NTM colonies. Pneumothorax was the only complication of the aspiration procedure. DISCUSSION: If the diagnostic criteria for pulmonary NTM diseases include positive culture in percutaneous aspiration material, the diagnosis of solitary nodular NTM lesions would become easier; at present, these lesions are often diagnosed only upon surgical resection. Further, clinical studies on the possibility of spontaneous shrinkage of the solitary lesion and the value of its medical treatment would be promoted. Aspiration can easily differentiate NTM disease from pulmonary abscess or fungal infection in patients with a solitary lesion or small cavity.

Factors of influenza vaccine inoculation and non-inoculation behavior of community-dwelling residents in Japan: Suggestions for vaccine policy and public health ethics after COVID-19.

The aim of this study is to provide basic information that contributes to vaccine inoculation policy after COVID-19. We used the secondary data of the influenza vaccine inoculation behavior survey for community-dwelling adults conducted in 2011, before the COVID-19 pandemic, but after the 2009 novel influenza A (H1N1) pdm 09 pandemic. All factors such as socio-demographic characteristics, health-related behaviors, family environment, physical and social environment, and area of residence were adjusted, and factors related to vaccine inoculation behavior were analyzed. Those living with pregnant women had a significantly higher odds ratio of inoculation; this was self-evident in that those people considered infection to their family. Regarding the social environment, those aged 20-64 years with a significantly higher adjusted odds ratio of inoculation were those with "at least five people with which they interacted in the neighborhood". This result can be interpreted in two ways relating to altruism in Japan. Finally, we indicated the importance of learning from the past, including the case of 2009.

Mechanisms and Minimization of False Discovery of Metabolic Bioorthogonal Noncanonical Amino Acid Proteomics.

Metabolic proteomics has been widely used to characterize dynamic protein networks in many areas of biomedicine, including in the arena of tissue aging and rejuvenation. Bioorthogonal noncanonical amino acid tagging (BONCAT) is based on mutant methionine-tRNA synthases (MetRS) that incorporates metabolic tags, for example, azidonorleucine [ANL], into newly synthesized proteins. BONCAT revolutionizes metabolic proteomics, because mutant MetRS transgene allows one to identify cell type-specific proteomes in mixed biological environments. This is not possible with other methods, such as stable isotope labeling with amino acids in cell culture, isobaric tags for relative and absolute quantitation and tandem mass tags. At the same time, an inherent weakness of BONCAT is that after click chemistry-based enrichment, all identified proteins are assumed to have been metabolically tagged, but there is no confirmation in mass spectrometry data that only tagged proteins are detected. As we show here, such assumption is incorrect and accurate negative controls uncover a surprisingly high degree of false positives in BONCAT proteomics. We show not only how to reveal the false discovery and thus improve the accuracy of the analyses and conclusions but also approaches for avoiding it through minimizing nonspecific detection of biotin, biotin-independent direct detection of metabolic tags, and improvement of signal to noise ratio through machine learning algorithms.

Old plasma dilution reduces human biological age: a clinical study.

This work extrapolates to humans the previous animal studies on blood heterochronicity and establishes a novel direct measurement of biological age. Our results support the hypothesis that, similar to mice, human aging is driven by age-imposed systemic molecular excess, the attenuation of which reverses biological age, defined in our work as a deregulation (noise) of 10 novel protein biomarkers. The results on biological age are strongly supported by the data, which demonstrates that rounds of therapeutic plasma exchange (TPE) promote a global shift to a younger systemic proteome, including youthfully restored pro-regenerative, anticancer, and apoptotic regulators and a youthful profile of myeloid/lymphoid markers in circulating cells, which have reduced cellular senescence and lower DNA damage. Mechanistically, the circulatory regulators of the JAK-STAT, MAPK, TGF-beta, NF-κB, and Toll-like receptor signaling pathways become more youthfully balanced through normalization of TLR4, which we define as a nodal point of this molecular rejuvenation. The significance of our findings is confirmed through big-data gene expression studies.

HSP90-buffered genetic variation is common in Arabidopsis thaliana.

HSP90 is a protein chaperone particularly important in the maturation of a diverse set of proteins that regulate key steps in a multitude of biological processes. Alterations in HSP90 function produce altered phenotypes at low penetrance in natural populations. Previous work has shown that at least some of these phenotypes are due to genetic variation that remains phenotypically cryptic until it is revealed by the impairment of HSP90 function. Exposure of such "buffered" genetic polymorphisms can also be accomplished by environmental stress, linking the appearance of new phenotypes to defects in protein homeostasis. Should such polymorphisms be widespread, natural selection may be more effective at producing phenotypic change in suboptimal environments. In evaluating this hypothesis, a key unknown factor is the frequency with which HSP90-buffered polymorphisms occur in natural populations. Here, we present Arabidopsis thaliana populations suitable for genetic mapping that have constitutively reduced HSP90 levels. We employ quantitative genetic techniques to examine the HSP90-dependent polymorphisms affecting a host of plastic plant life-history traits. Our results demonstrate that HSP90-dependent natural variation is present at high frequencies in A. thaliana, with an expectation that at least one HSP90-dependent polymorphism will affect nearly every quantitative trait in progeny of two different wild lines. Hence, HSP90 is likely to occupy a central position in the translation of genotypic variation into phenotypic differences.

Case Report: Therapeutic and immunomodulatory effects of plasmapheresis in long-haul COVID.

Many patients with COVID-19 experience a range of debilitating symptoms months after being infected, a syndrome termed long-haul COVID. A 68-year-old male presented with lung opacity, fatigue, physical and cognitive weaknesses, loss of smell and lymphocytopenia. After rounds of therapeutic plasma exchange (TPE), the patient returned to normal activities and work. Mechanistically in the patient's peripheral blood mononuclear cells (PBMCs), markers of inflammatory macrophages diminished and markers of lymphocytes, including natural killer (NK) cells and cytotoxic CD8 T-cells, increased. Circulating inflammatory proteins diminished, while positive regulators of tissue repair increased. This case study suggests that TPE has the capacity to treat long-haul COVID.

Perceptions of women and health-care providers in Tokyo of appropriate weight gain during pregnancy.

A mother's underweight status and insufficient weight gain during pregnancy are risk factors for infant low birthweight. Concerns have been raised regarding whether pregnant women are provided with accurate information about weight gain. This study explored how and from whom pregnant women in Tokyo receive information related to body weight. Four focus groups were conducted with nine pregnant women, nine nurse-midwives, and eight obstetricians between March and June 2006. The recorded interviews were content-analyzed. Weight gain was a common concern among the participants, regardless of the women's body size, and sufficient weight gain was rarely mentioned. However, the health-care providers were aware of their lack of expertise and training in behavior modification. Pregnant women consistently expressed a desire for reassurance and praise from health-care providers, which might be a culture-specific phenomenon. The findings point to a need for culturally appropriate and accurate communication about weight gain during pregnancy.

[Two cases of pulmonary amebiasis].

CASE 1: A 74-year-old man having a week's fever and diagnosed with a liver abscess was treated with several antibiotics and percutaneous liver drainage. His respiration gradually worsened and chest computed tomography (CT) showed right pleural effusion and a left-lung mass. Percutaneous fine needle aspiration of the pulmonary mass detected Entamoeba histolytica. CASE 2: A 44-year old, zoo office worker admitted for fever and right chest pain was found in CT to have right pleural effusion and a mass with a liver abscess necessitating abscess drainage. Injected contrast medium detected a fistula connected to the right. Following surgical drainage, E. histolytica was detected from the resected lung. Both cases responded well to metronidazole.

[A case of yellow nail syndrome with bilateral pleural effusion].

A 68-year-old woman, suffering from dyspnea on exertion, was admitted to our hospital. She had noticed her nails become yellow 8 years previously. She had mild bilateral effusion. Examination of the pleural fluid revealed exudates which were lymphocyte-rich, a high concentration of adenosine deaminase (ADA) and elevated serum levels of soluble interleukin-2 receptors. These confirmed the diagnosis of yellow nail syndrome.

[A relapse of acute bird-related hypersensitivity pneumonitis due to the use of a feather duvet by a housemate].

In December 2007, a 78-year-old woman was admitted to our hospital complaining of cough and low-grade fever for 1 month. We performed various medical tests and diagnosed acute hypersensitivity pneumonitis. We suspected that the cause of illness was the prolonged use (10 years) of a feather duvet. She was treated with corticosteroids and was advised to avoid using feather duvets. This treatment improved her symptoms. However, she relapsed after 1 year. She had never used a feather duvet since the last admission, but her housemate used a feather duvet in the same room during winter. Bronchoalveolar lavage revealed lymphocytosis. Specific antibodies against pigeon and budgerigar-dropping extracts were present in her serum. On the basis of these findings, we diagnosed acute bird-related hypersensitivity pneumonitis. This condition is rarely caused by indirect exposure. Therefore, we reiterate the significance of obtaining of a detailed medical history to identify relevant antigens.

Autonomous Continuation of Community Health Workers' Activities in Thegon Township, Bago Region, Myanmar.

Background: Few studies have reported on the autonomous continuation of Community Health Worker (CHW) activities after external supervision and support have ended. Objective: The study reports CHW activity continuation in Thegon Township, Bago Region, Myanmar, observed after the supervision by the external organization is completed. Method: Following the completion of a child nutrition program in Thegon Township, CHWs were left unsupervised and uninformed of a follow-up at 10, 23, and 40 months from the end of the program survey due to unforeseen circumstances. In a follow-up survey in 2014, data on the activity implementation status from CHWs and activity attendance from caregivers of the target children were collected. Focus group discussions were held with caregivers concerning their information sources on child nutrition and health. Results: On average, CHWs were found to have continued with 2.6 of the four core activities, often with modifications, irrespective of the time since completion of the non-profit-organization-led program. Meanwhile, caregiver attendance decreased over time. Caregivers recognized CHWs as information sources. Discussion: Although unsupervised, CHWs ambitiously continued with their activities, but sorted through and modified them, which may have been unrelated to the local acceptance of the program, as caregiver attendance decreased even as CHWs continued the activities. The observation may highlight the importance of proactive engagement and thus, the autonomy of CHWs in their activity continuation.

ATP depletion alters the mode of cell death induced by benzyl isothiocyanate.

Pro-inflammatory death is presumably an undesirable event in cancer prevention process, thus biochemical comprehension and molecular definition of this process could have important clinical implications. In the present study, we examined the cytophysiological conversion of cell death mode by benzyl isothiocyanate (BITC) in human cervical cancer HeLa cells. The detailed studies using flow cytometric and morphological analyses demonstrated that the cells treated with appropriate concentration (25 microM) of BITC showed apoptotic feature, such as chromatin condensation, DNA fragmentation, and preserved plasma membrane integrity, whereas these features were disappeared by treatment with higher concentration (100 microM). The treatment with 2-deoxyglucose, an inhibitor of ATP synthesis, drastically increased in the ratio of necrotic dead cells, while it influences little that of apoptotic cells. Moreover, an analysis using the mitochondrial DNA-deficient HeLa cells demonstrated that the rho degrees cells were more susceptible to the BITC-induced necrosis-like cell death compared to the wild-type (rho(+)) cells, whereas the ROS production was significantly inhibited in the rho degrees cells. It is likely that the BITC-induced ROS is derived from mitochondrial respiratory chain and ruled out the contribution to the mechanism of cell death mode switching. In addition, the BITC treatment resulted in a more rapid depletion of ATP in the rho degrees cells than in the rho(+) cells. Furthermore, a caspase inhibitor, Z-VAD-fmk counteracted not only apoptosis, but also necrosis-like cell death induced by BITC, suggesting that increment in this cell death pattern might be due to the interruption of events downstream of a caspase-dependent pathway. The obtained data suggested that the decline in the intracellular ATP level plays an important role in tuning the mode of cell death by BITC.

[A case of severe radiation pneumonitis--a trial of plasma exchange].

A 77-year-old man underwent radiotherapy for the squamous cell carcinoma of the right lung. Two months after the 60Gy/30fr irradiation was completed, he complained of dyspnea and his chest X-ray showed ground glass opacities and reticular shadows in both lung fields. Severe radiation pneumonitis was diagnosed. Two grams of methylprednisolone did not improve his symptoms and on the next day his hypoxemia worsened. We then tried plasma exchange because of his critical status. His respiratory status improved rapidly after plasma exchange and his chest X-ray showed remarkable improvement 10 days later. We think this case suggests the effectiveness of plasma exchange for severe radiation pneumonitis.

AtUBL5 regulates growth and development through pre-mRNA splicing in Arabidopsis thaliana.

Ubiquitin-like proteins play important roles in the regulation of many biological processes. UBL5 (Ubiquitin-like protein 5)/Hub1 (Homologous to ubiquitin 1), a member of the ubiquitin family, acts as a ubiquitin-like modifier on a specific target, the spliceosomal protein Snu66, in yeast and human cells. The 22nd aspartic acid (Asp22) is involved in the attachment of Hub1 to the Hub1 interaction domain (HIND) of Snu66 in yeast to modulate spliceosomal activity. Hub1 differs from other modifiers which interact covalently with their targets. It modulates pre-mRNA splicing by binding to Snu66 non-covalently in both yeast and human cells. However, the molecular mechanisms of Hub1-mediated pre-mRNA splicing in plant systems remains unclear. To better understand the function of Hub1 in plants, we examined the role of this ubiquitin-like modifier in Arabidopsis thaliana, which has two Hub1 homologues. Arabidopsis UBL5/Hub1(UBL5) is highly conserved at the amino acid level, compared to eukaryotic homologues in both plants and animals. In this study, phenotypic analysis of A. thaliana with reduced UBL5 gene expression, generated by RNA interference of AtUBL5a and AtUBL5b were performed. Interestingly, knock down plants of AtUBL5 showed abnormalities in root elongation, plant development, and auxin response. AtUBL5b is highly expressed in the vascular tissue of the leaf, stem, and root tissue. Yeast two-hybrid analysis revealed that AtUBL5a and AtUBL5b interact with the putative splicing factor AtPRP38 through its C-terminal domain (AtPRP38C). Knock down of AtUBL5b resulted in a pattern of insufficient pre-mRNA splicing in several introns of AtCDC2, and in introns of IAA1, IAA4, and IAA5. Defects of pre-mRNA splicing in an AtPRP38 mutant resulted in an insufficient pre-mRNA splicing pattern in the intron of IAA1. Based on these results, we showed that AtUBL5b positively regulates plant root elongation and development through pre-mRNA splicing with AtPRP38C in A. thaliana.