The mechanism of sperm-egg interaction and the involvement of IZUMO1 in fusion

Inoue, N., Ikawa, M., & Okabe, M. (2011). The mechanism of sperm-egg interaction and the involvement of IZUMO1 in fusion. Asian Journal of Andrology, 13(1), 81-87. doi:10.1038/aja.2010.7

Putative sperm fusion protein IZUMO and the role of N-glycosylation

IZUMO is the mouse sperm protein proven to be essential for fusion with eggs. It contains one immuno- globulin-like domain with a conserved glycosylation site within. In the present paper, we produced trans- genic mouse lines expressing unglycosylated IZUMO (N204Q-IZUMO) in Izumo1 / background. The expression of N204Q-IZUMO rescued the infertile phenotype of IZUMO disrupted mice, indicating glyco- sylation is not essential for fusion-facilitating activity of IZUMO. The N204Q-IZUMO was produced in tes- tis in comparable amounts to wild-type IZUMO, but the amount of N204Q-IZUMO on sperm was significantly decreased by the time sperm reached the cauda epididymis. These data suggest that glyco- sylation is not essential for the function of IZUMO, but has a role in protecting it from fragmentation in cauda epididymis

The mechanics clarifying counterclockwise rotation in most IVF eggs in mice

Ishimoto, K., Ikawa, M. & Okabe, M. The mechanics clarifying counterclockwise rotation in most IVF eggs in mice. Sci Rep 7, 43456 (2017). https://doi.org/10.1038/srep4345

Generation of Hprt-disrupted rat through mouse← rat ES chimeras

Isotani, A., Yamagata, K., Okabe, M. et al. Generation of Hprt-disrupted rat through mouse←rat ES chimeras. Sci Rep 6, 24215 (2016). https://doi.org/10.1038/srep2421

Mice expressing aberrant sperm-specific protein PMIS2 produce normal-looking but fertilization-incompetent spermatozoa

Yamaguchi, R., Fujiharaa, Y., Ikawa, M., & Okabe, M. (2012). Mice expressing aberrant sperm-specific protein PMIS2 produce normal-looking but fertilization-incompetent spermatozoa. Molecular Biology of the Cell, 23(14), 2671-2679. doi:10.1091/mbc.E11-12-102

Subaru Weak-Lensing Survey of Dark Matter Subhalos in the Coma Cluster : Subhalo Mass Function and Statistical Properties

We present a 4 deg^2 weak gravitational lensing survey of subhalos in the very nearby Coma cluster using the Subaru/Suprime-Cam. The large apparent size of cluster subhalos allows us to measure the mass of 32 subhalos detected in a model-independent manner, down to the order of 10^-3 of the virial mass of the cluster. Weak-lensing mass measurements of these shear-selected subhalos enable us to investigate subhalo properties and the correlation between subhalo masses and galaxy luminosities for the first time. The mean distortion profiles stacked over subhalos show a sharply truncated feature which is well-fitted by a Navarro-Frenk-White (NFW) mass model with the truncation radius, as expected due to tidal destruction by the main cluster. We also found that subhalo masses, truncation radii, and mass-to-light ratios decrease toward the cluster center. The subhalo mass function, dn/dln M_sub, in the range of 2 orders of magnitude in mass, is well described by a single power law or a Schechter function. Best-fit power indices of 1.09_-0.32^+0.42 for the former model and 0.99_-0.23^+0.34 for the latter, are in remarkable agreement with slopes of ~0.9-1.0 predicted by the cold dark matter paradigm. The tangential distortion signals in the radial range of 0.02-2Mpc/h from the cluster center show a complex structure which is well described by a composition of three mass components of subhalos, the NFW mass distribution as a smooth component of the main cluster, and a lensing model from a large scale structure behind the cluster. Although the lensing signals are 1 order of magnitude lower than those for clusters at z~0.2, the total signal-to-noise ratio, S/N=13.3, is comparable to, or higher, because the enormous number of background source galaxies compensates for the low lensing efficiency of the low lensing efficiency of the nearby cluster.Comment: 30 pages, 18 figures, 9 tables, ApJ in press. Full resolution version is available at http://www.asiaa.sinica.edu.tw/~okabe/files/coma_survey.pd

A One-Message Question in a Structured Interview: Investigating Psychological Needs of Children and Adolescents with Eating Disorders Directed toward Their Mothers

The purpose of this study was to investigate the psychological needs of children and adolescents with eating disorders (ED) directed toward their mothers. Patients with ED have low self-assertion and various abnormal eating behaviors. Therefore, mothers face difficulty in understanding their children's psychological needs, and the mother-child relationship is sometimes strained. We developed a One-Message Question (OMQ)-structured interview. The OMQ was easy to answer, and it helped the patients with ED. We examined the relationship between psychological needs and illness phase of the children and adolescents, and we discuss the viability of implementing the OMQ in clinical settings. The subjects were 23 patients and their parents. Their parents were just asked about the patients' background. The mean age of the patients was 15.8 years, and the average age of ED onset was 13.5 years. The EDs were anorexia nervosa (n＝20) and bulimia nervosa (n＝3). The phases of patients' illness were identified as anorexic (n＝5), bulimic (n＝7), chronic (n＝3), and stable (n＝8). All subjects provided specific responses to the OMQ-structured interview. Data analyses revealed the following seven categories of patients' psychological needs directed toward their mothers:attachment, cooperation in meeting their goals, longing for love, changing attitude toward family members, respect for self-reliance, expression of apology, and expression of appreciation. These findings suggested that the OMQ-structured interview may prove useful for mothers to understand their children's psychological needs and may encourage positive interactions as a foundation for future recovery

Identification and Disruption of Sperm-Specific Angiotensin Converting Enzyme-3 (ACE3) in Mouse

Background: IZUMO1 is the only sperm protein which is proven to be essential for sperm-egg fusion. However, the IZUMO1 is a structurally simple protein with single Ig domain and seems not to include either a ‘‘fusogenic peptide’ ’ or a fusion machinery domain. This led us to assume the existence of an IZUMO1-interacting protein(s) which makes a functional fusion machine interacting with IZUMO1. Methodology/Principal Findings: We produced a transgenic mouse line which expresses His-tagged IZUMO1 in the Izumo1 2/2 genetic background. After solubilization of sperm membranes, we purified His-tagged IZUMO1 using anti-His affinity chromatography and found a protein that interacts with IZUMO1. After being separated on SDS-PAGE gel, the IZUMO1-interacting protein was subjected to LC-MS/MS analysis and from the partial fragments, we identified the protein as ACE3. We raised the antibody against ACE3 and found that ACE3 is localized on the acrosomal cap area as in the case of IZUMO1. However, ACE3 disappeared from sperm after acrosome reaction while IZUMO1 remained on sperm. In order to investigate the role of ACE3 in vivo, we generated Ace3-deficient mice by homologous recombination and examined the fertilizing ability of the males. Unexpectedly, the male mice showed no defect in fertilizing ability in in vivo or in an in vitro fertilization system. Conclusions/Significance: We identified an IZUMO1-interacting protein in sperm, which we identified as testis specific AC

Transcriptional activation of a hybrid promoter composed of cytomegalovirus enhancer and β-actin/β-globin gene in glomerular epithelial cells in vivo

Transcriptional activation of a hybrid promoter composed of cytomegalovirus enhancer and β-actin/β-globin gene in glomerular epithelial cells in vivo. The aim of this study was to seek a promoter, transactivated selectively in renal cells in vivo by using transgenic (tg) mouse technology. We generated two kinds of tg mouse lines carrying a green fluorescence protein (GFP) cDNA driven either by cytomegalovirus enhancer and β-actin/β-globin promoter (CX-GFP) or by elongation factor la promoter (EF-GFP), and investigated the expression of GFP in the kidney. Microscopic examination of the renal tissues in CX-GFP-tg mice revealed that GFP was expressed only in glomeruli, mainly epithelial cells, but not in tubules, arteries and interstitium. Moreover, in situ hybridization demonstrated that GFP mRNA expression was localized in the glomerular cells. In contrast, GFP was not detectable in the kidney in any of the lines of EF-GFP-tg mouse. To exclude the possible involvement of the GFP cDNA as an enhancer, we constructed tg mice carrying the CX promoter driving a human CD4 cDNA. It was confirmed that the expression patterns of human CD4 in the kidney were quite similar to those of GFP in the kidney of CX-GFP-tg mice. These results strongly suggest that CX promoter could be transactivated in glomerular epithelial cells in vivo