Figure 5.

Oocyte-specific knockout of Lonp1 impairs mitochondrial biosynthesis and function. (a) Representative pictures of Lonp1^loxp/loxp (upper) and Lonp1^Gdf9Cre cKO (lower) mouse MII oocytes stained with JC‐1 (from 4-week-old mice of each genotype). Scale bar=50 μm. (b) Ratios of red:green JC‐1 fluorescence in Lonp1^loxp/loxp and Lonp1^Gdf9Cre cKO mouse MII oocytes (n>24) from at least six mice (****p < 0.0001, Student's t test). (c) Representative pictures of Lonp1^loxp/loxp (upper panel) and Lonp1^Gdf9Cre cKO (lower panel) mouse MII oocytes stained with MitoTracker Green and MitoSOX (from 4-week-old mice of each genotype). Scale bar = 50 μm. (d) Ratios of MitoSOX:MitoTracker Green fluorescence in Lonp1^loxp/loxp and Lonp1^Gdf9Cre cKO mouse MII oocytes (n>32) from at least six mice (****p < 0.0001, Student's t test). (e–g) qRT-PCR analysis of the expression of COX4i-1, Sdhb and Ndufa12 in Lonp1^loxp/loxp and Lonp1^Gdf9Cre cKO mouse MII oocytes (n=6, *p < 0.05, **p < 0.01, Student's t test). (h) mtDNA copy numbers in oocytes from 5-week-old Lonp1^loxp/loxp and Lonp1^Gdf9Cre cKO mice (at least six MII oocytes were included, *p < 0.05, Student's t test). (i) Representative immunofluorescence images showing the mitochondrial distributions in 4-week-old Lonp1^loxp/loxp (upper) and Lonp1^Gdf9Cre cKO (lower) mouse GV oocytes. Scale bar = 50 μm. (j) Representative TEM images showing mitochondria in GV oocytes from 3-, 4-, and 5-week-old Lonp1^loxp/loxp (upper panel) and Lonp1^Gdf9Cre cKO (lower panel) mice (n=3 for each genotype). M indicates mitochondria. Scale bar=0.2 μm. (k) TUNEL staining of oocytes from Lonp1^loxp/loxp and Lonp1^Gdf9Cre cKO mice (n=6). Scale bar = 50 μm.