RPA and γH2AX signals were severely reduced in sycp2-/- spermatocytes.A: Staining of sycp2+/+ and sycp2-/- spermatocyte chromosomal spreads with anti-human RPA, anti-Sycp1 and anti-Sycp3 antibodies. Note that the human RPA protein (NP_002936.1) shares 63.5% identity and 80.9% similarity with the zebrafish protein (NP_956105.2). In sycp2+/+ spermatocytes, RPA appears at leptonema in faint foci, which become brighter at zygonema and disappear at pachynema. In sycp2-/- spermatocytes, RPA foci were rarely detected; only a few foci were observed in some cells. B: Immunostaining of sycp2+/+ (i, ii) and sycp2-/- (iii, iv) spermatocyte chromosomal spreads with anti-γH2AX, anti-Sycp3 and Sycp1 antibodies. Individual images with each antibody and a merged image are shown. The wild-type (sycp2+/+) nuclei are at early to mid-zygonema. Scale bars, 5 μm.
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