Deletion of Exoc7, but not Exoc3, in male germ cells causes severe spermatogenesis failure with spermatocyte aggregation in mice

Vesicular trafficking is essential for the transport of intracellularly produced functional molecules to the plasma membrane and extracellular space. The exocyst complex, composed of eight different proteins, is an important functional machinery for "tethering" in vesicular trafficking. Functional studies have been conducted in laboratory mice to identify the mechanisms by which the deletion of each exocyst factor affect various biological phenomena. Interestingly, each exocyst factor-deficient mutant exhibits a different phenotype. This discrepancy may be due to the function of the exocyst factor beyond its role as a component of the exocyst complex. Male germline-specific conditional knockout (cKO) mice of the Exoc1 gene, which encodes one of the exocyst factors EXOC1 (SEC3), exhibit severe spermatogenesis defects; however, whether this abnormality also occurs in mutants lacking other exocyst factors remains unknown. In this study, we found that exocyst factor EXOC3 (SEC6) was not required for spermatogenesis, but depletion of EXOC7 (EXO70) led to severe spermatogenesis defects. In addition to being a component of the exocyst complex, EXOC1 has other functions. Notably, male germ cell-specific Exoc7 cKO and Exoc1 cKO mice exhibited phenotypic similarities, suggesting the importance of the exocyst complex for spermatogenesis. The results of this study will contribute to further understanding of spermatogenesis from the aspect of vesicular trafficking.

DAJIN enables multiplex genotyping to simultaneously validate intended and unintended target genome editing outcomes

Genome editing can introduce designed mutations into a target genomic site. Recent research has revealed that it can also induce various unintended events such as structural variations, small indels, and substitutions at, and in some cases, away from the target site. These rearrangements may result in confounding phenotypes in biomedical research samples and cause a concern in clinical or agricultural applications. However, current genotyping methods do not allow a comprehensive analysis of diverse mutations for phasing and mosaic variant detection. Here, we developed a genotyping method with an on-target site analysis software named Determine Allele mutations and Judge Intended genotype by Nanopore sequencer (DAJIN) that can automatically identify and classify both intended and unintended diverse mutations, including point mutations, deletions, inversions, and cis double knock-in at single-nucleotide resolution. Our approach with DAJIN can handle approximately 100 samples under different editing conditions in a single run. With its high versatility, scalability, and convenience, DAJIN-assisted multiplex genotyping may become a new standard for validating genome editing outcomes.

Efficient induction of proximity-dependent labelling by biotin feeding in BMAL1-BioID knock-in mice

Proximity-dependent biotin identification (BioID) is a useful method to identify unknown protein-protein interactions. Few reports have described genetically engineered knock-in mouse models for in vivo BioID. Thus, little is known about the proper method for biotin administration and which tissues are applicable. Here, we established a BioID knock-in mouse model of Brain and Muscle ARNT-Like 1 (BMAL1) and the BirA biotin ligase with R118G mutation (BirA*). The BMAL1-BioID mouse model was used to investigate the effect of biotin diet feeding on protein biotinylation in several tissues. The BMAL1-BirA* fusion protein-retained proper intracellular localization of BMAL1 and binding to CLOCK protein in HEK293T cells. A biotin labelling assay in mouse embryonic fibroblasts revealed the protein biotinylation activity of BMAL1-BirA* expressed in knock-in mouse cells depending on biotin supplementation. Lastly, feeding a 0.5% biotin diet for 7 days induced protein biotinylation in the brain, heart, testis and liver of BMAL1-BioID mice without adverse effects on spermatogenesis. In the kidney, the biotin diet increased biotinylated protein levels in BMAL1-BioID and control mice, suggesting the existence of endogenous biotinylation activity. These results provide valuable information to optimize the in vivo BioID procedure.

EXOC1 plays an integral role in spermatogonia pseudopod elongation and spermatocyte stable syncytium formation in mice

The male germ cells must adopt the correct morphology at each differentiation stage for proper spermatogenesis. The spermatogonia regulates its differentiation state by its own migration. The male germ cells differentiate and mature with the formation of syncytia, failure of forming the appropriate syncytia results in the arrest at the spermatocyte stage. However, the detailed molecular mechanisms of male germ cell morphological regulation are unknown. Here, we found that EXOC1, a member of the Exocyst complex, is important for the pseudopod formation of spermatogonia and spermatocyte syncytia in mice. EXOC1 contributes to the pseudopod formation of spermatogonia by inactivating the Rho family small GTPase Rac1 and also functions in the spermatocyte syncytia with the SNARE proteins STX2 and SNAP23. Since EXOC1 is known to bind to several cell morphogenesis factors, this study is expected to be the starting point for the discovery of many morphological regulators of male germ cells.

Citrullinated inter-alpha-trypsin inhibitor heavy chain 4 in arthritic joints and its potential effect in the neutrophil migration

The citrullinated inter-alpha-trypsin inhibitor heavy chain 4 (cit-ITIH4) was identified as its blood level was associated with the arthritis score in peptide glucose-6-phosphate-isomerase-induced arthritis (pGIA) mice and the disease activity in patients with rheumatoid arthritis (RA). This study aimed to clarify its citrullination pathway and function as related to neutrophils. In pGIA-afflicted joints, ITIH4 and cit-ITIH4 levels were examined by immunohistochemistry (IHC), immunoprecipitation (IP) and Western blotting (WB), while peptidylarginine deiminase (PAD) expression was measured by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), IHC and immunofluorescent methods. The pGIA mice received anti-lymphocyte antigen 6 complex locus G6D (Ly6G) antibodies to deplete neutrophils and the expression of cit-ITIH4 was investigated by WB. The amounts of ITIH4 and cit-ITIH4 in synovial fluid (SF) from RA and osteoarthritis (OA) patients were examined by I.P. and W.B. Recombinant ITIH4 and cit-ITIH4 were incubated with sera from healthy volunteers before its chemotactic ability and C5a level were evaluated using Boyden's chamber assay and enzyme-linked immunosorbent assay (ELISA). During peak arthritic phase, ITIH4 and cit-ITIH4 were increased in joints while PAD4 was over-expressed, especially in the infiltrating neutrophils of pGIA mice. Levels of cit-ITIH4 in plasma and joints significantly decreased upon neutrophil depletion. ITIH4 was specifically citrullinated in SF from RA patients compared with OA patients. Native ITIH4 inhibited neutrophilic migration and decreased C5a levels, while cit-ITIH4 increased its migration and C5a levels significantly. Cit-ITIH4 is generated mainly in inflamed joints by neutrophils via PAD4. Citrullination of ITIH4 may change its function to up-regulate neutrophilic migration by activating the complement cascade, exacerbating arthritis.

Generation of B6-Ddx4em1(CreERT2)Utr , a novel CreERT2 knock-in line, for germ cell lineage by CRISPR/Cas9

Germ cell development is essential for maintaining reproduction in animals. In postpubertal females, oogenesis is a highly complicated event for producing fertilizable oocytes. It starts when dormant primordial oocytes undergo activation to become growing oocytes. In postpubertal males, spermatogenesis is a differentiation process for producing sperm from spermatogonial stem cells. To obtain full understanding of the molecular mechanisms underlying germ cell development, the Cre/loxP system has been widely applied for conditional knock-out mouse studies. In this study, we established a novel knock-in mouse line, B6-Ddx4 ^{em1(CreERT2)Utr} , which expresses CreERT2 recombinase under the control of the endogenous DEAD-box helicase 4 (Ddx4) gene promoter. Ddx4 was specifically expressed in both female and male germ cell lineages. We mated the CreERT2 mice with R26GRR mice, expressing enhanced green fluorescent protein (EGFP) and tDsRed before and after Cre recombination. We found tDsRed signals in the testes and ovaries of tamoxifen-treated B6-Ddx4 ^{em1(CreERT2)Utr} ::R26GRR mice, but not in untreated mice. Immunostaining of their ovaries clearly showed that Cre recombination occurred in all oocytes at every follicle stage. We also found 100% Cre recombination efficiency in male germ cells via the progeny test. In summary, our results indicate that B6-Ddx4 ^{em1(CreERT2)Utr} is beneficial for studying female and male germ cell development.

Infrared and ab Initio Studies on 1,2,4,5-Tetrafluorobenzene Clusters with Methanol and 2,2,2-Trifluoroethanol: Presence and Absence of an Aromatic C−H···O Hydrogen Bond

The (1:1) clusters of 1,2,4,5-tetrafluorobenzene (TFB) with methanol and with 2,2,2-trifluoroethanol (TFE) were studied both experimentally and computationally. Through use of fluorescence-detected infrared spectroscopy, the (1:1) clusters were identified in supersonic jets. Intermolecular interactions in the clusters were characterized by the spectral shifts of the aromatic C-H stretching modes in the TFB moiety owing to the cluster formation. The molecular structures, stabilization energies, and vibrational frequencies of the clusters were computed at the MP2/6-31+G level. Both computational and experimental data indicate that an aromatic C-H...O hydrogen bond is present in the TFB-methanol cluster, while it is absent in the TFB-TFE cluster.

Observation of the nuCH Excited Vibrational Levels in the Ã1A" State of HCP by IR-UV Double Resonance Spectroscopy

Rovibrational levels with one quantum of CH stretch mode, (1, v2, v3), in the Ã1A" electronic state of HCP were observed for the first time by IR-UV double resonance spectroscopy. Nine vibrational levels were identified in the energy region of 37 500-40 800 cm-1. Perturbations similar to those in the (0, v2, v3) levels were also observed in many of the vibrational levels. It was found that the CH stretch frequency in the Ã1A" state is reduced about 270 cm-1 relative to that of the electronic ground state. Copyright 1999 Academic Press.

Alexithymic characteristics in responses to the Synthetic House-Tree-Person (HTP) Drawing Test

This study examined the association of certain complex personality traits assessed by the Synthetic House-Tree-Person Drawing Test and alexithymic characteristics assessed by the 20-item Toronto Alexithymia Scale for a sample of 589 Japanese college students. Alexithymic students who scored over 61 points on the Toronto Alexithymia Scale-20 exhibited two characteristics relative to the test: poor relationships between figures and additional written explanations. These two characteristics projected on the Synthetic House-Tree-Person Drawing Test may be related to alexithymic characteristics and related factors.

[Relationship between ultrasound-findings of low-echoic nodule of hepatic parenchyma in liver cirrhosis and development of hepatocellular carcinoma]

We investigated development of hepatocellular carcinoma (HCC) in 90 patients with liver cirrhosis by follow up study for a period from 6 months to three and half years, making special reference to ultrasound-findings of the parenchyma of the liver. Liver cirrhosis was classified into four types and two, non-nodular and nodular, groups according to low-echoic nodules distributed in the parenchyma. The development of HCC was higher at the rate of incidence in patients of the nodular group than those of the non-nodular. It was more closely related with the male in patients of the non-nodular group, and both the old age and the advanced hepatic injury in those of the nodular group. A rise of the level of serum AFP during a period of the follow up was not observed in relation to the development of HCC and seemed to be ineffective for detection of carcinoma small sized. The echo-types of the parenchyma in liver cirrhosis were most significantly correlated with the development of HCC in comparison with the other etiologic factors.