Close association between vasa-positive germ plasm granules and mitochondria correlates with cytoplasmic localization of 12S and 16S mtrRNAs during zebrafish spermatogenesis

VASA-induced cytoplasmic localization of CYTB-positive mitochondrial substance occurs by destructive and nondestructive mitochondrial effusion, respectively, in early and late spermatogenic cells of the Manila clam

“…Considering that the release of mitochondrial material might not always mean the destruction of mitochondria, a kind of functional release of mitochondrial material into the cytoplasm can be assumed. Recently, it was shown that during spermatogenesis of zebrafish, mitochondria, into which VASA entered, released mitochondrial ribosomal subunits, 12S mtrRNA and 16S mtrRNA, into the cytoplasm (Reunov et al 2019b). This observation obviously adds to the arguments in favor of hypothesis (1).…”

“…The role of mitochondrial material release can be summarized by two current hypotheses: (1) the release of mitochondrial ribosomes may replace cellular ribosomes during early embryogenesis, oogenesis (Kobayashi 1993(Kobayashi , 1998Amikura et al 2001Amikura et al , 2005 and spermatogenesis Breitbart 2006, 2008;Villegas et al 2002;Reunov et al 2019b), or/and (2) the selection of healthy mitochondria occurs along with the elimination of less performing mitochondria (Ghiselli et al 2019). According to what observed in the early phases of spermatogenesis, the catastrophic process can be theoretically account for hypothesis (2), given the strong reduction in mitochondrial number happening in such stages.…”