Ignificantly larger (M-ASPM = 37.7563.80 mm, average6STDEV) (Figure 5B). Similarly, the uninjected and injected control oocytes had similar values of D1 (Control = 18.2464.90 mm, M-Control = 15.9765.21 mm, average6STDEV) and D2 (Control = 26.8765.06 mm, M-Control = 29.0465.27 mm, average6STDEV), both of which were significantly different from the ASPM morpholino-injected group (D1, M-ASPM = 10.7864.31 mm and D2, MASPM = 21.4864.69 mm, average 6 STDEV).The Spindle Protein Calmodulin Co-immunoprecipitated with 25033180 ASPMThe detection of ASPM at the meiotic spindle and downregulation of ASPM led to an abnormal meiotic spindle and inhibited meiotic progression prompted us to investigate whether ASPM co-localized with specific spindle-associated proteins to control spindle assembly. Lysates from MEFs and mouse MI-stage oocytes were used for the studies. The immunoprecipitation (IP) of ASPM from lysates followed by mass spectrometry identified a peptide absent from control IPs that corresponded to calmodulin (data not shown). Further western blot analysis confirmed the expression of calmodulin as a 20-kDa band in the IP elution lane; the same bands were detected in control MEF cell lysates but not in the IP-control lane (Figure 6A). These results indicated that ASPM co-immunoprecipitated with calmodulin in the MEFs and in the mouse oocytes. Therefore, we next tested the localization of ASPM and calmodulin during mouse oocyte meiosis. We found that ASPM and calmodulin colocalized at the spindles of MI and MII oocytes (Figure 6B).Downregulation of ASPM by a Gene-specific Morpholino Disrupts Meiotic Spindle Assembly and Meiosis ProcessionGene-specific morpholino oligonucleotides have proven to be an effective approach for gene knockdown in mouse oocytes [21,22]. Western blot analyses revealed that ASPM protein expression was reduced by 49.14 in mouse oocytes by microinjecting ASPM-specific morpholino oligonucleotides (Figure 3). After 18 h of culture, DAPI-labeled DNA configurations were assessed to determine the progression of meiosis in each group of mouse oocytes (Table 1). Of the total oocytes evaluated, 83.48 and 70.85 progressed to MII in the uninjected control group and the control morpholino group, respectively; however, in the ASPM morpholino group, only 19.51 of the oocytes progressed to MII, while most remained at MI. This result indicated that the decrease in the expression of ASPM greatly disrupted the meiotic progression. To further evaluate the functional effects of the downregulation of ASPM expression, the oocytes were examined by immunofluorescence. As shown in Figure 4, ASPM depletion led to abnormal spindle assembly. Elongated spindles were frequently observed in oocytes with reduced expression of ASPM, while disorganized spindles lacking intact poles were also found (Figure 4B). Abnormal meiotic MI and MII spindle organization was observed in 13.33 and 11.06 of the uninjected control oocytes and in 4.34 and 12.45 of the oocytes injected with morpholinoDiscussionIn this study, we JSI-124 site provide the first evidence that ASPM is a conserved microtubule-associated protein that plays an essential role in the control of spindle organization during mouse oocyte meiotic maturation. The perturbation of ASPM function causes meiotic spindle assembly defects, and first polar body extrusion (PBE) greatly decreased when ASPM was Dimethylenastron web partially inhibited. Previous reports have shown that ASPM colocalizes with ctubulin at the spindle poles during mito.Ignificantly larger (M-ASPM = 37.7563.80 mm, average6STDEV) (Figure 5B). Similarly, the uninjected and injected control oocytes had similar values of D1 (Control = 18.2464.90 mm, M-Control = 15.9765.21 mm, average6STDEV) and D2 (Control = 26.8765.06 mm, M-Control = 29.0465.27 mm, average6STDEV), both of which were significantly different from the ASPM morpholino-injected group (D1, M-ASPM = 10.7864.31 mm and D2, MASPM = 21.4864.69 mm, average 6 STDEV).The Spindle Protein Calmodulin Co-immunoprecipitated with 25033180 ASPMThe detection of ASPM at the meiotic spindle and downregulation of ASPM led to an abnormal meiotic spindle and inhibited meiotic progression prompted us to investigate whether ASPM co-localized with specific spindle-associated proteins to control spindle assembly. Lysates from MEFs and mouse MI-stage oocytes were used for the studies. The immunoprecipitation (IP) of ASPM from lysates followed by mass spectrometry identified a peptide absent from control IPs that corresponded to calmodulin (data not shown). Further western blot analysis confirmed the expression of calmodulin as a 20-kDa band in the IP elution lane; the same bands were detected in control MEF cell lysates but not in the IP-control lane (Figure 6A). These results indicated that ASPM co-immunoprecipitated with calmodulin in the MEFs and in the mouse oocytes. Therefore, we next tested the localization of ASPM and calmodulin during mouse oocyte meiosis. We found that ASPM and calmodulin colocalized at the spindles of MI and MII oocytes (Figure 6B).Downregulation of ASPM by a Gene-specific Morpholino Disrupts Meiotic Spindle Assembly and Meiosis ProcessionGene-specific morpholino oligonucleotides have proven to be an effective approach for gene knockdown in mouse oocytes [21,22]. Western blot analyses revealed that ASPM protein expression was reduced by 49.14 in mouse oocytes by microinjecting ASPM-specific morpholino oligonucleotides (Figure 3). After 18 h of culture, DAPI-labeled DNA configurations were assessed to determine the progression of meiosis in each group of mouse oocytes (Table 1). Of the total oocytes evaluated, 83.48 and 70.85 progressed to MII in the uninjected control group and the control morpholino group, respectively; however, in the ASPM morpholino group, only 19.51 of the oocytes progressed to MII, while most remained at MI. This result indicated that the decrease in the expression of ASPM greatly disrupted the meiotic progression. To further evaluate the functional effects of the downregulation of ASPM expression, the oocytes were examined by immunofluorescence. As shown in Figure 4, ASPM depletion led to abnormal spindle assembly. Elongated spindles were frequently observed in oocytes with reduced expression of ASPM, while disorganized spindles lacking intact poles were also found (Figure 4B). Abnormal meiotic MI and MII spindle organization was observed in 13.33 and 11.06 of the uninjected control oocytes and in 4.34 and 12.45 of the oocytes injected with morpholinoDiscussionIn this study, we provide the first evidence that ASPM is a conserved microtubule-associated protein that plays an essential role in the control of spindle organization during mouse oocyte meiotic maturation. The perturbation of ASPM function causes meiotic spindle assembly defects, and first polar body extrusion (PBE) greatly decreased when ASPM was partially inhibited. Previous reports have shown that ASPM colocalizes with ctubulin at the spindle poles during mito.
