All Phenotypes Mael<tm1Bort> MGI Mouse

abnormal spermatocyte morphology ( J:140402 )

• only 8% of the p10 and 70% of p20 seminiferous tubules contain spermatocytes compared to 21% of wild-type tubules at p10 and 90% of tubules at p15

• the number of spermatocytes found in tubules drops after p20 due to cell degeneration

• abnormal pachytene spermatocytes have compact nuclei while others develop expanded nuclei with scattered chromatin

abnormal male meiosis ( J:140402 )

• some spermatocytes fail to complete meiotic prophase I

• only a minority of spermatocytes (9%) reach the pachytene stage and less than 1% of spermatocytes reached diplonema

• abnormal pachytene spermatocytes exhibit compact nuclei while others develop expanded nuclei with scattered chromatin

• defects in homologous chromosome synapsis is detected in most mice including high levels of double stranded breaks, univalents, and nuclei combining zygotene and pachytene features

• these abnormal spermatocytes go into apoptosis

increased male germ cell apoptosis ( J:140402 )

• spermatocytes have increased rates of apoptosis to the point that every seminiferous tubule of a 56-day old male has evidence of apoptotic germ cells

abnormal DNA methylation during gametogenesis ( J:140402 )

• the 5' untranslated region of the L1 transposon is not methylated in male germ cells leading to high expression of the transposon and subsequent genomic damage

small testis ( J:140402 )

• the testis of adult males are visibly smaller

male infertility ( J:140402 )

• male mice fail to sire offspring