saturation, and original image for brightness.
The output images were inverted for better
visualization of the results.
Reanalysis of previously published RNA-seq data
Previously published bulk and single-cell RNA-
seq datasets for oocytes and preimplantation
embryos from mice (GSE44183) ( 97 ), cows
(GSE52415) ( 98 ), pigs (GSE139512) ( 101 ), and
humans (GSE44183, GSE101571, GSE133856,
and GSEE154762) ( 97 , 99 , 100 , 102 )weredown-
loaded from the Gene Expression Omnibus
(NIH). To compare gene expression levels be-
tween different samples from the same data-
set, reads per kilobase of transcript per million
reads mapped (RPKM) and fragments per
kilobase of transcript per million reads mapped
(FPKM) were converted into transcripts per
million (TPM). TPM has been shown to better
represent transcript abundance at the gene
level than RPKM and FPKM because it re-
spects the invariance property and is pro-
portional to the average relative RNA molar
concentration of the transcript in a sample
( 139 , 140 ).
Quantification of fluorescence recovery after
photobleaching experiments
Minor temporal drift was corrected using Rigid
registration in Icy. Mean intensities of photo-
bleached areas over time were exported from
Fiji into Excel for further processing. Data were
first corrected for background by subtracting
the intensity of an area outside the oocytes.
Background-corrected data were then nor-
malized to the intensity of prebleached time
points (F 0 ). Plots of intensity (F) against time
were fitted to single exponential functions
[F(t)=c−F∞e−t/t, wherecis the offset,F∞is
the amplitude of maximum intensity recov-
ered after equilibrium, andtis the time con-
stant] in OriginPro. Half-times of maximum
recovery (t1/2) and mobile fractions were deter-
mined byt× ln(2) andF∞/(F 0 −−F′) (whereF′
is the minimum intensity measured immedi-
ately after photobleaching), respectively.
Statistical analysis
No statistical methods were used to predeter-
mine sample size. The experiments were not
randomized. The investigators were not blinded
to allocation during experiments and outcome
assessment. Average (mean) and SD were cal-
culated in Excel. Statistical significance is based
on unpaired, two-tailed Student’sttest (for
absolute values) and two-tailed Fisher’s exact
test (for categorical values), which were calcu-
lated in Prism (GraphPad), assuming normal
distribution and similar variance. All box plots
show median (horizontal black line), mean
(small black squares), 25th and 75th percentiles
(boxes), 5th and 95th percentiles (whiskers),
and 1st and 99th percentiles (crosses). All data
are from at least two independent experi-
ments.Pvalues are designated as *P< 0.05,
**P< 0.01, ***P< 0.001, and ****P< 0.0001.
Nonsignificant values are indicated as N.S.REFERENCESANDNOTES- J. R. Gruhnet al., Chromosome errors in human eggs shape
natural fertility over reproductive life span.Science 365 ,
1466 – 1469 (2019). doi:10.1126/science.aav7321;
pmid: 31604276 - Z. Holubcová, M. Blayney, K. Elder, M. Schuh, Error-prone
chromosome-mediated spindle assembly favors chromosome
segregation defects in human oocytes.Science 348 ,
1143 – 1147 (2015). doi:10.1126/science.aaa9529;
pmid: 26045437 - J. Haverfieldet al., Tri-directional anaphases as a novel
chromosome segregation defect in human oocytes.Hum.
Reprod. 32 , 1293–1303 (2017). doi:10.1093/humrep/
dex083; pmid: 28449121 - A. H. Sathananthanet al., Centrioles in the beginning of
human development.Proc. Natl. Acad. Sci. U.S.A. 88 ,
4806 – 4810 (1991). doi:10.1073/pnas.88.11.4806;
pmid: 2052559 - M. Plachot, N. Crozet, Fertilization abnormalities in human
in-vitro fertilization.Hum. Reprod. 7 , 89–94 (1992).
doi:10.1093/humrep/7.suppl_1.89; pmid: 1447374 - H. Balakier, Tripronuclear human zygotes: The first cell cycle
and subsequent development.Hum. Reprod. 8 , 1892– 1897
(1993). doi:10.1093/oxfordjournals.humrep.a137955;
pmid: 8288756 - A. H. Sathananthanet al., The sperm centriole: Its
inheritance, replication and perpetuation in early human
embryos.Hum. Reprod. 11 , 345–356 (1996). doi:10.1093/
HUMREP/11.2.345; pmid: 8671223 - M. Moomjy, L. T. Colombero, L. L. Veeck, Z. Rosenwaks,
G. D. Palermo, Sperm integrity is critical for normal mitotic
division and early embryonic development.Mol. Hum. Reprod.
5 , 836–844 (1999). doi:10.1093/molehr/5.9.836;
pmid: 10460222 - Y. F. Gu, G. Lin, C. F. Lu, G. X. Lu, Analysis of the first mitotic
spindles in human in vitro fertilized tripronuclear zygotes
after pronuclear removal.Reprod. Biomed. Online 19 ,
745 – 754 (2009). doi:10.1016/j.rbmo.2009.09.013;
pmid: 20021725 - Y. Kai, K. Iwata, Y. Iba, Y. Mio, Diagnosis of abnormal human
fertilization status based on pronuclear origin and/or
centrosome number.J. Assist. Reprod. Genet. 32 , 1589– 1595
(2015). doi:10.1007/s10815-015-0568-1; pmid: 26395191 - Y. F. Guet al., Abnormalities in centrosome number in
human embryos and embryonic stem cells.Mol. Reprod.
Dev. 83 , 392–404 (2016). doi:10.1002/mrd.22633;
pmid: 26946049 - Y. Kai, H. Moriwaki, K. Yumoto, K. Iwata, Y. Mio, Assessment
of developmental potential of human single pronucleated
zygotes derived from conventional in vitro fertilization.J.
Assist. Reprod. Genet. 35 , 1377–1384 (2018). doi:10.1007/
s10815-018-1241-2; pmid: 29959619 - E. Fordet al., The first mitotic division of the human embryo
is highly error-prone.bioRxiv2020.2007.2017.208744
[Preprint] (2020); .doi:10.1101/2020.07.17.208744 - Y. Kai, H. Kawano, N. Yamashita, First mitotic spindle
formation is led by sperm centrosome-dependent MTOCs in
humans.Reproduction 161 , V19–V22 (2021). doi:10.1530/
REP-21-0061; pmid: 33843613 - S. Santaguida, A. Amon, Short- and long-term effects of
chromosome mis-segregation and aneuploidy.Nat. Rev. Mol.
Cell Biol. 16 , 473–485 (2015). doi:10.1038/nrm4025;
pmid: 26204159 - P. T. Conduit, A. Wainman, J. W. Raff, Centrosome function
and assembly in animal cells.Nat. Rev. Mol. Cell Biol. 16 ,
611 – 624 (2015). doi:10.1038/nrm4062; pmid: 26373263 - P. Meraldi, Centrosomes in spindle organization and
chromosome segregation: A mechanistic view.Chromosome
Res. 24 , 19–34 (2016). doi:10.1007/s10577-015-9508-2;
pmid: 26643311 - H. Maiato, E. Logarinho, Mitotic spindle multipolarity without
centrosome amplification.Nat. Cell Biol. 16 , 386–394 (2014).
doi:10.1038/ncb2958; pmid: 24914434 - D. Szollosi, P. Calarco, R. P. Donahue, Absence of centrioles
in the first and second meiotic spindles of mouse oocytes.
J. Cell Sci. 11 , 521–541 (1972). doi:10.1242/jcs.11.2.521;
pmid: 5076360
20. A. H. Sathananthan, Ultrastructural changes during meiotic
maturation in mammalian oocytes: Unique aspects of the
human oocyte.Microsc. Res. Tech. 27 , 145–164 (1994).
doi:10.1002/jemt.1070270208; pmid: 8123907
21. G. Manandhar, H. Schatten, P. Sutovsky, Centrosome
reduction during gametogenesis and its significance.Biol.
Reprod. 72 ,2–13 (2005). doi:10.1095/
biolreprod.104.031245; pmid: 15385423
22. M. Hatsumi, S. A. Endow, Mutants of the microtubule motor
protein, nonclaret disjunctional, affect spindle structure and
chromosome movement in meiosis and mitosis.J. Cell Sci.
101 , 547–559 (1992). doi:10.1242/jcs.101.3.547;
pmid: 1522143
23. H. J. Matthies, H. B. McDonald, L. S. Goldstein, W. E. Theurkauf,
Anastral meiotic spindle morphogenesis: Role of the non-claret
disjunctional kinesin-like protein.J. Cell Biol. 134 , 455– 464
(1996). doi:10.1083/jcb.134.2.455; pmid: 8707829
24. R. Healdet al., Self-organization of microtubules into bipolar
spindles around artificial chromosomes inXenopusegg
extracts.Nature 382 , 420–425 (1996). doi:10.1038/
382420a0; pmid: 8684481
25. R. Heald, R. Tournebize, A. Habermann, E. Karsenti, A. Hyman,
Spindle assembly inXenopusegg extracts: Respective roles
of centrosomes and microtubule self-organization.J. Cell Biol.
138 , 615–628 (1997). doi:10.1083/jcb.138.3.615;
pmid: 9245790
26. K. P. McNally, F. J. McNally, The spindle assembly function of
Caenorhabditis eleganskatanin does not require microtubule-
severing activity.Mol. Biol. Cell 22 , 1550–1560 (2011).
doi:10.1091/mbc.e10-12-0951; pmid: 21372175
27. A. A. Connollyet al.,Caenorhabditis elegansoocyte meiotic
spindle pole assembly requires microtubule severing and
the calponin homology domain protein ASPM-1.Mol. Biol. Cell
25 , 1298–1311 (2014). doi:10.1091/mbc.e13-11-0687;
pmid: 24554763
28. S. J. Radford, A. M. M. Go, K. S. McKim, Cooperation between
kinesin motors promotes spindle symmetry and chromosome
organization in oocytes.Genetics 205 , 517–527 (2017).
doi:10.1534/genetics.116.194647; pmid: 27932541
29. G. Cavin-Meza, M. M. Kwan, S. M. Wignall, Multiple motors
cooperate to establish and maintain acentrosomal spindle
bipolarity inC. elegansoocyte meiosis.bioRxiv
2021.2009.2009.459640 [Preprint] (2021); doi:10.1101/
2021.09.09.459640
30. M. Schuh, J. Ellenberg, Self-organization of MTOCs replaces
centrosome function during acentrosomal spindle assembly
in live mouse oocytes.Cell 130 , 484–498 (2007).
doi:10.1016/j.cell.2007.06.025; pmid: 17693257
31. C. Soet al., A liquid-like spindle domain promotes acentrosomal
spindle assembly in mammalian oocytes.Science 364 , eaat9557
(2019). doi:10.1126/science.aat9557; pmid: 31249032
32. X. Guo, S. Gao, Pins homolog LGN regulates meiotic spindle
organization in mouse oocytes.Cell Res. 19 , 838– 848
(2009). doi:10.1038/cr.2009.54; pmid: 19434098
33. A. Kolano, S. Brunet, A. D. Silk, D. W. Cleveland, M. H. Verlhac,
Error-prone mammalian female meiosis from silencing the
spindle assembly checkpoint without normal interkinetochore
tension.Proc. Natl. Acad. Sci. U.S.A. 109 , E1858–E1867 (2012).
doi:10.1073/pnas.1204686109; pmid: 22552228
34. D. Clift, M. Schuh, A three-step MTOC fragmentation
mechanism facilitates bipolar spindle assembly in mouse
oocytes.Nat. Commun. 6 , 7217 (2015). doi:10.1038/
ncomms8217; pmid: 26147444
35. A. Z. Balboulaet al., Haspin kinase regulates microtubule-
organizing center clustering and stability through Aurora kinase
C in mouse oocytes.J. Cell Sci. 129 , 3648–3660 (2016).
doi:10.1242/jcs.189340; pmid: 27562071
36. Y. H. Kim, I. W. Lee, Y. J. Jo, N. H. Kim, S. Namgoong, Acentriolar
microtubule organization centers and Ran-mediated
microtubule formation pathways are both required in porcine
oocytes.Mol. Reprod. Dev. 86 , 972–983 (2019). doi:10.1002/
mrd.23172; pmid: 31136049
37. J. Lee, T. Miyano, R. M. Moor, Spindle formation and
dynamics ofg-tubulin and nuclear mitotic apparatus protein
distribution during meiosis in pig and mouse oocytes.Biol.
Reprod. 62 , 1184–1192 (2000). doi:10.1095/
biolreprod62.5.1184; pmid: 10775165
38. M. R. Shin, N. H. Kim, Maternal gamma (g)-tubulin is involved
in microtubule reorganization during bovine fertilization
and parthenogenesis.Mol. Reprod. Dev. 64 , 438–445 (2003).
doi:10.1002/mrd.10280; pmid: 12589656
39. C. Alvarez Sedó, H. Schatten, C. M. Combelles, V. Y. Rawe,
The nuclear mitotic apparatus (NuMA) protein: Localization
Soet al.,Science 375 , eabj3944 (2022) 11 February 2022 17 of 19
RESEARCH | RESEARCH ARTICLE