The widespread use of Wi-Fi-derived radiofrequency electromagnetic radiation (RF-EMR) has raised concerns regarding male reproductive health; however, whether paternal exposure exerts transgenerational effects on offspring development remains unclear. This study investigated the effects of chronic paternal 2.4 GHz Wi-Fi RF-EMR exposure (whole-body SAR 0.125-0.5 W/kg, 4 h/day, 6 days/week for 20 weeks) on sperm quality in F0 male mice and placental development in F1 offspring, with a focus on epigenetic regulation. Paternal RF-EMR exposure significantly reduced sperm concentration and increased the sperm abnormality rate in F0 males. F1 offspring exhibited reduced fetal weight and placental efficiency, with more pronounced impairments in male offspring. Mechanistically, paternal exposure reduced the proportion of placental labyrinth layer and downregulated multiple nutrient transporters in a male-biased manner. Epigenetic analysis revealed sex-dependent histone modifications in placentas following paternal RF-EMR exposure: male placentas exhibited increased H3K9me2/3, H3K27me3, H3K27ac, and H3K4me2, whereas female placentas exhibited decreased H3K4me2. ChIP-qPCR targeting transporter promoters revealed sex-specific enrichment of repressive histone marks in placentas from exposed fathers. In male placentas, H3K27me3 was increased at the Atp1a1 and Slc22a3 promoters, and H3K9me3 was increased at the Atp1a1 and Slc2a1 promoters. In female placentas, H3K27me3 at the Slc3a2 promoter was significantly decreased. Collectively, chronic paternal Wi-Fi RF-EMR exposure impairs fetal growth and placental efficiency, with male offspring being more susceptible, and is associated with disrupted placental structure, impaired nutrient transport, and sex-dependent histone modifications in the offspring placenta. These findings underscore the importance of considering paternal RF-EMR exposure in reproductive risk assessment.

Background:Liver allograft fibrosis (LAF) is prevalent among children with long-term survival after liver transplantation (LT). The authors aimed to identify clinical risk factors, with a focus on the impact of immunosuppression (IS) level in the early post-transplant period on LAF.Methods:A retrospective study was conducted on pediatric LT recipients with at least 1-year of follow-up. Cox regression models were used to analyze risk factors associated with LAF, and landmark analysis was used to evaluate the impact of IS level on LAF. Longitudinal analysis was also conducted in patients with paired biopsies.Results:A total of 139 patients involving 174 liver biopsies were included. With 2.3 to 5.9 years of follow-up, LAF was detected in 91.4% of patients (7.9% were significant), up to 88.2% of whom showed normal liver function. Episodes of acute rejection, biliary complications, cytomegalovirus infection, and prolonged cold ischemia time were independent risk factors. Besides, the risk of LAF in patients with relatively low IS levels at postoperative 1-3, 3-6, 6-12, and 12-36 months was higher than the counterparts. Especially, in patients with relatively high IS levels (mean tacrolimus trough concentration >= 5.1 ng/ml) during postoperative 12-36 months, the risk of LAF was 67% lower in the short future (P=0.006). In paired analysis, patients with increased IS levels were more likely to achieve fibrosis-reduction (HR=7.53, P=0.025).Conclusions:Mild to moderate LAF is common among pediatric LT recipients and can appear early and silently. Maintaining adequate levels of IS during 1-3 years after LT seems crucial to ensure protection against LAF.

BACKGROUND:Primary hyperoxaluria type 1 (PH1) is a rare autosomal recessive disease stemming from a deficiency in liver-specific alanine-glyoxylate aminotransferase, resulting in increased endogenous oxalate deposition and end-stage renal disease. Organ transplantation is the only effective treatment. However, its approach and timing remain controversial.CASE SUMMARY:We retrospectively analyzed 5 patients diagnosed with PH1 from the Liver Transplant Center of the Beijing Friendship Hospital from March 2017 to December 2020. Our cohort included 4 males and 1 female. The median age at onset was 4.0 years (range: 1.0-5.0), age at diagnosis was 12.2 years (range: 6.7-23.5), age at liver transplantation (LT) was 12.2 years (range: 7.0-25.1), and the follow-up time was 26.3 mo (range: 12.8-40.1). All patients had delayed diagnosis, and 3 patients had progressed to end-stage renal disease by the time they were diagnosed. Two patients received preemptive LT; their estimated glomerular filtration rate was maintained at > 120 mL/min/1.73 m2, indicating a better prognosis. Three patients received sequential liver and kidney transplantation. After transplantation, serum and urinary oxalate decreased, and liver function recovered. At the last follow-up, the estimated glomerular filtration rates of the latter 3 patients were 179, 52 and 21 mL/min/1.73 m2.CONCLUSION:Different transplantation strategies should be adopted for patients based on their renal function stage. Preemptive-LT offers a good therapeutic approach for PH1.

Nowadays, concerns about the harmful effects of radiofrequency electromagnetic radiation (RF-EMR) on male fertility and offspring health are growing. In the present study, we investigated the effects of long-term exposure (at least 10 weeks) to the RF-EMR [2.0 GHz; power density, 2.5 W/m(2); whole-body specific absorption rate (SAR), 0.125-0.5 W/kg] on male mice fertility and F1 growth and glucose metabolism. No significant injuries were observed in testis organization, sperm quality, and pregnancy rate. However, mice exposed to RF-EMR exhibited a significantly elevated apoptosis rate in testis germ cells. Interestingly, paternal RF-EMR exposure resulted in sex-specific weight trajectory differences and glucose metabolism changes in male F1 mice but not in female F1 mice. The changed glucose metabolism in F1 male may result from the altered gene expression of liver Gck. These data collectively suggested that 2.0 GHz RF-EMR whole-body exposure of male mice does not cause obvious impairment in testis, sperm quality, and pregnancy rate. Paternal RF-EMR exposure causes male-specific alterations in body weight trajectories and glucose metabolism of F1.

Background Current world experience regarding living donor liver transplantation (LDLT) in the treatment of propionic acidemia (PA) is limited, especially in terms of using obligate heterozygous carriers as donors. This study aimed to evaluate the clinical outcomes of LDLT in children with PA. Methods From November 2017 to January 2020, 7 of the 192 children who underwent LDLT at our institution had been diagnosed with PA (median age, 2.1 years; range, 1.1–5.8 years). The primary indication for transplantation was frequent metabolic decompensations in 6 patients and preventative treatment in 1 patient. Of the seven parental living donors, six were genetically proven obligate heterozygous carriers. Results During a median follow-up of 23.9 months (range, 13.9–40.2 months), all patients were alive with 100% allograft survival, and no severe transplant-related complications occurred. In the case of liberalized protein intake, they did not suffer metabolic decompensation or disease-related complications and made progress in neurodevelopmental delay and body growth, as well as blood and urinary metabolite levels. In one patient with pre-existing mild dilated cardiomyopathy, her echocardiogram results completely normalized 13.8 months post-transplant. All living donors recovered well after surgery, with no metabolic decompensations or procedure-related complications. Western blotting revealed that the hepatic expressions of PCCA and PCCB in one of the heterozygous donors were comparable to those of the normal healthy control at the protein level. Conclusions LDLT using partial liver grafts from asymptomatic obligate heterozygous carrier donors is a viable therapeutic option for selected PA patients, with no negative impact on donors’ and recipients' clinical courses.

Objective: To investigate the clinical effect and prognosis of liver transplantation for familial hypercholesterolemia(FH). Method: A retrospective analysis was performed on the preoperative characteristics, operative conditions and postoperative follow-up of 5 children who received liver transplantation for familial hypercholesterolemia admitted to our center from December 2014 to July 2021. Result: The patients’ primary clinical manifestation was a progressive increase of palpable yellow masses in buttocks and joints and decreased activity tolerance, accompanied by increased blood cholesterol and low-density lipoprotein. Case 1 had multiple coronary artery stenosis and intra-arterial lipid plaque formation. Case 2 had severe stenosis of the coeliac trunk, multiple stenoses of neck vessels, and repeated chest tightness and precardiac pain after exercise. Case 3 had carotid intima-media thickening and right subclavian artery plaque formation. Case 4 showed uneven thickening of intima-media membranes of bilateral external iliac arteries and bilateral carotid arteries. Case 5 showed slight thickening of intima-media membrane at the beginning of bilateral carotid arteries and right subclavian artery, and slight stenosis of descending aorta. All patients were confirmed to have FH by genetic test and biochemical blood test. Case 2 gene test was compound heterozygous LDLR mutation (exon6; c.920A>G); case 3 gene test was compound heterozygous LDLR mutation (①exon4; c.G665T; ②exon14; c.C2054T); case 4 was homozygous LDLR mutation (exon7; c.G952T>C); case 5 was a composite heterozygous LDLR mutation (①exon5; c.727T>A; ②exon9; c.1187-10G>A). The age of the first onset were 6 years, 4 years, 2 years, 1 year, and 1 year, respectively. All 5 children were male, with the preoperative blood cholesterol level of 15.33±4.67mmol/L and the blood LDL level of 10.69±2.80mmol/L. Preoperative low-fat diet and lipid-lowering drugs, including rosuvastatin, ezetimibe, probucco and Xuzhikang, had poor efficacy. They received liver transplantation at 149, 124, 92, 45 and 72 months, and all donor livers were from cadavers. On the first day after liver transplantation, their blood cholesterol level was 5.56±1.88mmol/L and their LDL level was 4.06±1.75mmol/L. The liver function of 5 patients recovered gradually, blood cholesterol was in the normal range and normal diet was resumed. The patients have been followed up for 80.7, 24.1, 11.3, 9.6 and 6 months. All the children have survived healthy. The cardiovascular diseases of the 5 children have not shown significant progress in postoperative follow-up so far. The clinical manifestations such as suffocating, squatting and precardiac discomfort were significantly reduced after operation. Conclusion: Liver transplantation is a means to cure FH. It should be performed before the occurrence of cardiovascular diseases in children, and satisfactory quality of life can be achieved after transplantation.

Background Pulmonary infection is a common complication in pediatric living donor liver transplantation (LDLT) recipients. It has been suggested that vitamin D has a role in immune defense against infection. Therefore, we investigated the effect of preoperative serum 25-hydroxyvitamin D-3(25(OH)D-3) on the risk of pneumonia in hospitalized patients undergoing LDLT. Materials and Methods This study was a retrospective review of patient records. Fifty consecutive pediatric patients (aged < 14 years) who underwent LDLT from January 2017 to December 2017 were included. Pulmonary infection in the early postoperative period was diagnosed using clinical, radiological, or laboratory criteria. Preoperative serum 25(OH)D(3)level, demographic characteristics, primary diagnosis, ascites, time to extubation, length of intensive care unit stay, and perioperative laboratory values were recorded. Vitamin D deficiency, insufficiency, and sufficiency were defined as a serum 25(OH)D(3)concentration of less than 10, 10 to 20, and more than 20 ng/mL, respectively. Associations between serum 25(OH)D(3)levels and pulmonary infection were analyzed. Results Of 50 pediatric patients who underwent LDLT, 19 (38%) developed pulmonary infections in the early postoperative period. The mean serum 25(OH)D(3)level in these subjects was 18.7 +/- 17.2 ng/mL (range, 3.0-70.0 ng/mL). Twenty patients (40%) had severe vitamin D deficiency (<10 ng/mL). The mean serum 25(OH)D(3)level was significantly decreased (9.3 +/- 7.4 vs 24.5 +/- 19.1 ng/mL,P = .002) in patients with pulmonary infection compared with those without pulmonary infection. Serum 25(OH)D(3)level as a continuous variable (odds ratio [OR], 0.90, 95% confidence interval [CI], 0.84-0.97,P = .008) and a classification variable (<= 10 ng/mL) (OR, 7.42, 95% CI, 2.06-26.79,P = .002) were significantly associated with pulmonary infection in univariate analysis. After adjusting for other significant predictors (age, weight, and pediatric end-stage liver disease score), severe 25(OH)D(3)deficiency at presentation was independently associated with a higher risk of developing pulmonary infection in the early postoperative period (OR, 5.11, 95% CI, 1.30-20.16,P = .02). Conclusions 25(OH)D(3)deficiency is common and inversely correlated with pulmonary infection within the first month after pediatric LDLT. Our results indicate that preoperative serum 25(OH)D(3)deficiency is a potential biomarker for early pulmonary infection after pediatric LDLT.

Systemic 1,25(OH)2D3 treatment ameliorating murine inflammatory bowel diseases (IBD) could not be applied to patients because of hypercalcemia. We tested the hypothesis that increasing 1,25(OH)2D3 synthesis locally by targeting delivery of the 1α-hydroxylase gene (CYP27B1) to the inflamed bowel would ameliorate IBD without causing hypercalcemia. Our targeting strategy is the use of CD11b(+)/Gr1(+) monocytes as the cell vehicle and a macrophage-specific promoter (Mac1) to control CYP27B1 expression. The CD11b(+)/Gr1(+) monocytes migrated initially to inflamed colon and some healthy tissues in dextran sulfate sodium (DSS) colitis mice; however, only the migration of monocytes to the inflamed colon was sustained. Adoptive transfer of Gr1(+) monocytes did not cause hepatic injury. Infusion of Mac1-CYP27B1-modified monocytes increased body weight gain, survival, and colon length, and expedited mucosal regeneration. Expression of pathogenic Th17 and Th1 cytokines (interleukin (IL)-17a and interferon (IFN)-α) was decreased, while expression of protective Th2 cytokines (IL-5 and IL-13) was increased, by the treatment. This therapy also enhanced tight junction gene expression in the colon. No hypercalcemia occurred following this therapy. In conclusion, we have for the first time obtained proof-of-principle evidence for a novel monocyte-based adoptive CYP27B1 gene therapy using a mouse IBD model. This strategy could be developed into a novel therapy for IBD and other autoimmune diseases.

The direct conversion of skin cells into somatic stem cells has opened new therapeutic possibilities in regenerative medicine. Here, we show that human induced mesenchymal stem cells (iMSCs) can be efficiently generated from cord blood (CB)- or adult peripheral blood (PB)-CD34+ cells by direct reprogramming with a single factor, OCT4. In the presence of a GSK3 inhibitor, 16% of the OCT4-transduced CD34+ cells are converted into iMSCs within 2 weeks. Efficient direct reprogramming is achieved with both episomal vector-mediated transient OCT4 expression and lentiviral vector-mediated OCT4 transduction. The iMSCs express MSC markers, resemble bone marrow (BM)-MSCs in morphology, and possess in vitro multilineage differentiation capacity, yet have a greater proliferative capacity compared with BM-MSCs. Similar to BM-MSCs, the implanted iMSCs form bone and connective tissues, and are non-tumorigenic in mice. However, BM-MSCs do not, whereas iMSCs do form muscle fibers, indicating a potential functional advantage of iMSCs. In addition, we observed that a high level of OCT4 expression is required for the initial reprogramming and the optimal iMSC self-renewal, while a reduction of OCT4 expression is required for multilineage differentiation. Our method will contribute to the generation of patient-specific iMSCs, which could have applications in regenerative medicine. This discovery may also facilitate the development of strategies for direct conversion of blood cells into other types of cells of clinical importance.

The ability to efficiently generate integration-free induced pluripotent stem cells (iPSCs) from the most readily available source-peripheral blood-has the potential to expedite the advances of iPSC-based therapies. We have successfully generated integration-free iPSCs from cord blood (CB) CD34(+) cells with improved oriP/EBNA1-based episomal vectors (EV) using a strong spleen focus forming virus ( SFFV) long terminal repeat (LTR) promoter. Here we show that Yamanaka factors (OCT4, SOX2, MYC, and KLF4)-expressing EV can also reprogram adult peripheral blood mononuclear cells (PBMNCs) into pluripotency, yet at a very low efficiency. We found that inclusion of BCL-XL increases the reprogramming efficiency by approximately 10-fold. Furthermore, culture of CD3(-)/CD19(-) cells or T/B cell-depleted MNCs for 4-6 days led to the generation of 20-30 iPSC colonies from 1 ml PB, an efficiency that is substantially higher than previously reported. PB iPSCs express pluripotency markers, form teratomas, and can be induced to differentiate in vitro into mesenchymal stem cells, cardiomyocytes, and hepatocytes. Used together, our optimized factor combination and reprogramming strategy lead to efficient generation of integration-free iPSCs from adult PB. This discovery has potential applications in iPSC banking, disease modeling and regenerative medicine.

The reprogramming of cord blood (CB) cells into induced pluripotent stem cells (iPSCs) has potential applications in regenerative medicine by converting CB banks into iPSC banks for allogeneic cell replacement therapy. Therefore, further investigation into novel approaches for efficient reprogramming is necessary. Here, we show that the lentiviral expression of OCT4 together with SOX2 (OS) driven by a strong spleen focus-forming virus (SFFV) promoter in a single vector can convert 2% of CB CD34(+) cells into iPSCs without additional reprogramming factors. Reprogramming efficiency was found to be critically dependent upon expression levels of OS. To generate transgene-free iPSCs, we developed an improved episomal vector with a woodchuck post-transcriptional regulatory element (Wpre) that increases transgene expression by 50%. With this vector, we successfully generated transgene-free iPSCs using OS alone. In conclusion, high-level expression of OS alone is sufficient for efficient reprogramming of CB CD34(+) cells into iPSCs. This report is the first to describe the generation of transgene-free iPSCs with the use of OCT4 and SOX2 alone. These findings have important implications for the clinical applications of iPSCs.

Proprotein convertase 5/6 (PC6) is a member of the proprotein convertase family that endoproteolytically cleave latent precursor proteins into their biologically active state. We have previously demonstrated that endometrial PC6 is critical for embryo implantation in mice and primates, including human. PC6 regulates the endometrial physiology specifically at implantation in association with epithelial differentiation during the establishment of endometrial receptivity (in human and monkey) and stromal cell decidualization (in the mouse, human and monkey). PC6 was further confirmed to be a unique PC member that is tightly regulated in the endometrium in relation to implantation. Our further studies (unpublished) suggest that PC6 regulates adhesion molecules in the endometrial epithelium for implantation in women. It is known that between the mouse and human, the endometrial stroma-mediated responses are similar whereas the epithelial cells behave differently. Because PC6 regulates primarily the stromal component (decidualization) in the mouse, in vivo mouse models are critical to investigate the roles of PC6 in decidualization. To address the function of PC6 in endometrial epithelium, non-mouse models relevant to human implantation are required. The rabbit is regarded as an excellent model to study the molecular events of embryo adhesion and attachment. The current study aimed to determine the expression pattern and localisation of PC6 in the rabbit uterus during early pregnancy. Quantitative RT-PCR analysis showed that PC6 mRNA expression was dynamically up-regulated in the rabbit uterus immediately prior to implantation. Western blotting and immunohistochemical analyses demonstrated that PC6 protein was predominantly localised to the basal glands throughout pregnancy, and up-regulated specifically in the epithelium at the embryo attachment site. These findings suggest that PC6 may play an essential role in rabbit implantation, and that the rabbit is a useful animal model to investigate the function of PC6 during embryo attachment.

Reprogramming human somatic cells to pluripotency represents a valuable resource for research aiming at the development of in vitro models for human diseases and regenerative medicines to produce patient-specific induced pluripotent stem (iPS) cells. Seeking appropriate cell resources for higher efficiency and reducing the risk of viral transgene activation, especially oncogene activation, are of significance for iPS cell research. In this study, we tested whether human amnion-derived cells (hADCs) could be rapidly and efficiently reprogrammed into iPS cells by the defined factors: OCT4/SOX2/NANOG. hADCs from normal placenta were isolated and cultured. The 3rd passage cells were infected with the lentiviral vectors for the delivery of OCT4, SOX2, and NANOG. Afterwards, the generated iPSCs were identified by morphology, pluripotency markers, global gene expression profiles, and epigenetic status both in vitro and in vivo. The results showed that we were able to reprogram hADCs by the defined factors (OCT4/SOX2/NANOG). The efficiency was significantly high (about 0.1%), and the typical colonies appeared on the 9th day after infection. They were similar to human embryonic stem (ES) cells in morphology, proliferation, surface markers, gene expression, and the epigenetic status of pluripotent cell-specific genes. Furthermore, these cells were able to differentiate into various cell types of all three germ layers both in vitro and in vivo. These results demonstrate that hADCs were an ideal somatic cell resource for the rapid and efficient generation of iPS cells by OCT4/SOX2/NANOG.

目的:体外建立表皮细胞去分化模型,为深入阐明表皮细胞去分化过程奠定基础。方法:离体条件下选择热损伤与碱性成纤维细胞生长因子（bFGF）作为联合诱导因素处理成熟表皮细胞。通过Giemsa染色和电镜观察细胞形态的改变;通过细胞培养和滋养层培养体系观察细胞的增殖能力,包括克隆形成和复层生长情况;采用器官培养体系体外构建三维皮肤,观察细胞再分化形成表皮情况;应用基因芯片技术观察细胞基因表达的改变。结果:经联合诱导后,细胞形态发生改变。表现为体积减小,细胞器数目减少,核浆比增大。增殖和再分化能力的改变体现在诱导后的表皮细胞能形成克隆,在滋养层培养条件下可以形成复层生长,并能够在体外构建出包括基底层和基底上层在内的表皮结构。基因水平的改变表现为与角质化相关基因下调和与有丝分裂相关基因上调。结论:在热损伤与bFGF联合诱导下,已分化的表皮细胞会发生形态、功能和基因表达的改变,表现为干细胞的特性。

We have compared the micro-RNAs expressed in mature oocytes, 2-cell, 8-cell and blastocyst stage embryos both qualitatively and quantitatively using the miRNA micro-arrays with a total of 509 human, rat, mouse, and predicted miRNA probes. The discovered miRNAs were classified into 5 groups according to the expression pattern including: oocyte, 2-cell embryo, 8-cell embryo, blastocyst specific and generally expressed group. Potential gene targets of each group of miRNA were estimated by TargetsScan system. Gene targets from different group of miRNA were compared with that of the generally expressed group and significantly changed represented signaling pathways, biological processes and molecules were determined using PANTHER classification system. A total of 94 miRNAs differentially expressed both qualitatively and quantitatively were found in this study, among which 39 were not listed or didn't have a mouse homolog. A total of 37 biological processes and 7 signaling pathways were over-represented (or less-represented) by the target genes of generally expressed miRNAs. Oocyte miRNAs were characterized by targeting to an enhanced Notch signaling pathway, carbohydrate metabolism and ligase, a decreased protein folding, cell adhesion molecule and signaling molecule; 2-cell stage embryo miRNAs were characterized by targeting to an enhanced sulfur metabolism, protein metabolism/modification, calcium binding proteins and a decreased cell adhesion molecule; 8-cell stage embryo miRNAs were characterized by targeting to an enhanced cell adhesion-mediating signaling, phosphatase and dehydrogenase; blastocyst stage embryo miRNAs were characterized by targeting to an enhanced action potential propagation, RNA and nucleic acid binding protein. We conclude that: 1. In mice genome, there were likely to be additional miRNA target sites that were not conserved across all mammals; 2. Specific biological progresses and signaling pathways were controlled by the specifically expressed miRNAs in preimplantation mouse embryos; 3. Stage-specific expression of miRNAs in oocytes and different developmental stage embryos might represent specific roles of each miRNA for early embryonic developmental control, such as maternal mRNA degradation.

Consistent with our previous study, we herein offer further evidence to demonstrate the dedifferentiation of differentiating epidermal cells into stem cells or stem cells -like in vivo. The epidermal sheets eliminated of basal cells were labeled with 6-diamidino-2-phenylindole (DAPI), and then were transplanted onto the full-thickness skin wounds nude mice. Immunohistochemical examination of the survival sheets showed that some cells were positive for both DAPI and either cytokeratins (CK19, CK14) or beta1 integrin in spinous and granular layers at day 7 after transplantation. Furthermore, there was a significant increase in the percentages of both alpha6briCDdim and alpha6briCD71bri populations in survival epidermal sheet grafts 7 d after transplantation compared with those before xenotransplantation (P<0.05), as determined by flow cytometry. The results collectively indicated that some of the differentiated cells in engrafted epidermal sheets dedifferentiated into stem cells or stem cells-like in vivo, which offer us new evidence and insights into the dedifferentiation.

BACKGROUND & AIMS:Molecular misreading of the ubiquitin B gene has been documented in the cerebral cortex of patients with Alzheimer's disease and Down syndrome. This novel process consists of the unfaithful conversion of genomic information into aberrant transcripts and its subsequent translation into +1 proteins.METHODS:Because Mallory bodies (MBs) also contain ubiquitinated proteins, we stained 11 autopsied and 6 biopsied MB-containing livers from patients with steatohepatitis with an antibody to ubiquitin(+1) to look for the presence of mutant (ubiquitin(+1)) protein. Antibodies to wild-type ubiquitin were used to document the presence of MBs in all cases.RESULTS:Ubiquitin(+1) immunoreactivity was detected in all MB-containing livers with steatohepatitis; no ubiquitin(+1) immunoreactivity was found in 13 MB-free liver controls. A subpopulation (about one third of the MBs) of the MB-containing hepatocytes in autopsied livers showed ubiquitin(+1) immunoreactivity (i.e., ubiquitin and ubiquitin(+1) colocalized in MBs). MB-containing liver biopsy specimens showed colocalization of ubiquitin and ubiquitin(+1) in every MB. Western blot analysis showed an ubiquitin(+1) band of 11 kilodaltons. Molecular misreading of the ubiquitin B gene (DeltaGU) was shown in one of the livers, which contained numerous MBs using an expression cloning strategy.CONCLUSIONS:The results showed that molecular misreading of the ubiquitin B gene occurred in hepatocytes in virtually all of the MB-containing livers tested. Ubiquitin(+1) protein was only found within the MBs and therefore may act by interfering with the degradation of the MBs because ubiquitin(+1) may inhibit proteolytic function of the proteasome.