BAX, a heterodimeric partner of BCL2, counters BCL2 and promotes apoptosis in gain-of-function experiments. A Bax knockout mouse was generated that proved viable but displayed lineage-specific aberrations in cell death. Thymocytes and B cells in this mouse displayed hyperplasia, and Bax-deficient ovaries contained unusual atretic follicles with excess granulosa cells. In contrast, Bax-deficient males were infertile as a result of disordered seminiferous tubules with an accumulation of atypical premeiotic germ cells, but no mature haploid sperm. Multinucleated giant cells and dysplastic cells accompanied massive cell death. Thus, the loss of Bax results in hyperplasia or hypoplasia, depending on the cellular context.

http://science.sciencemag.org/content/sci/270/5233/96.full.pdf

Bax-deficient mice with lymphoid hyperplasia and male germ cell death

cDNA Cloning of MCT2, a Second Monocarboxylate Transporter Expressed in Different Cells than MCT1

Immortalization of germ cells and somatic testicular cells using the SV40 large T antigen.

https://www.jbc.org/content/273/44/28959.full.pdf

Human monocarboxylate transporter 2 (MCT2) is a high affinity pyruvate transporter.

The fibrous sheath is a cytoskeletal structure located in the principal piece of mammalian sperm flagella Previous studies showed that glyceraldehyde 3-phosphate dehydrogenase, spermatogenic (GAPDHS), a germ cell-specific glycolytic isozyme that is required for sperm motility, is tightly bound to the fibrous sheath To determine if other glycolytic enzymes are also bound to this cytoskeletal structure, we isolated highly purified fibrous sheath preparations from mouse epididymal sperm using a sequential extraction procedure The isolated fibrous sheaths retain typical ultrastructural features and exhibit little contamination by axonemal or outer dense fiber proteins in Western blot analyses Proteomic analysis using peptide-mass fingerprinting and MS/MS peptide fragment ion matching identified GAPDHS and two additional glycolytic enzyme subunits, the A isoform of aldolase 1 (ALDOA) and lactate dehydrogenase A (LDHA), in isolated fibrous sheaths The presence of glycolytic enzymes in the fibrous sheath was also examined by Western blotting In addition to GAPDHS, ALDOA, and LDHA, this method determined that pyruvate kinase is also tightly bound to the fibrous sheath These data support a role for the fibrous sheath as a scaffold for anchoring multiple glycolytic enzymes along the length of the flagellum to provide a localized source of ATP that is essential for sperm motility

/pdf/multiple-glycolytic-enzymes-are-tightly-bound-to-the-fibrous-e44fpixord.pdf

Marie Hintz

Papers

Immunohistochemical localization of LDH-x during spermatogenesis in mouse testes.

Analyses of Stage-Specific Multiple Forms of Lactate Dehydrogenase and of Cytochrome c during Spermatogenesis in the Mouse