Developmental expression, intracellular localization, and selenium content of the cysteine-rich protein associated with the mitochondrial capsules of mouse sperm

Quantitative analysis of mRNA translation in mammalian spermatogenic cells with sucrose and Nycodenz gradients

“…Fraction 4 contains ~0.6% of the total Smcp mRNA on the gradient. The absence of a peak of Smcp mRNA in fraction 4, implies that the levels of polysomal Smcp mRNA are negligible at this age, in agreement with the observation that the most advanced spermatids in 26 dpp testis are ~step 9, and therefore lack the step 11-16 spermatids in which the SMCP protein is detected [18]. …”

“…Our estimate for the Smcp mRNA in 21 dpp testis is 5- to 10-fold lower than those obtained by RT-qPCR and microarray analysis in 22 dpp testis, 19 and 39%, respectively [3]. We believe those numbers are much too high, and do not accurately reflect the strong repression of the Smcp mRNA in early spermatids [4,6,18]. …”

Targeting of a Germ Cell-specific Type 1 Hexokinase Lacking a Porin-binding Domain to the Mitochondria as Well as to the Head and Fibrous Sheath of Murine Spermatozoa

“…The third possibility raised by the localization of HK1-sc to mitochondria is that HK1-sc binds to the mitochondria of sperm via a completely different interaction. Sperm mitochondria are surrounded by a keratinous mitochondrial capsule (Cataldo et al, 1996), which might even necessitate a different means of localization. Regardless of mechanism, the finding that an isoform of HK1 can localize to the mitochondria without a classical PBD is intriguing and deserves further examination.…”

Expression of a Novel, Sterol-Insensitive Form of Sterol Regulatory Element Binding Protein 2 (SREBP2) in Male Germ Cells Suggests Important Cell- and Stage-Specific Functions for SREBP Targets during Spermatogenesis

“…4C), such that contributions by the more efficiently translated mRNAs in testicular somatic cells (e.g., Sertoli, peritubular, and Leydig cells) are apparent. The distribution of the germ cell-enriched 2.5-kb mRNA in the denser gradient fractions is very similar to that for most other mRNAs translated in adult spermatogenic cells, such as LDH-C and Sp1 (7,23,36). Thus, SREBP2gc mRNA is actively translated in mouse adult male germ cells at levels typical of mRNAs expressed during spermatogenesis.…”