All Phenotypes Tbpl1<tm1Saco> MGI Mouse

decreased germ cell number ( J:68789 )

• only a few elongating spermatids survive stage 7, due to massive apoptosis of round spermatids at this stage

• rare surviving cells degenerate and never progress beyond stage 13

azoospermia ( J:68789 )

• the seminal fluid of male homozygotes lacks mature spermatozoa

• no mature spermatozoa are detected in the seminiferous tubules or epididymis

increased male germ cell apoptosis ( J:68789 )

• round spermatids undergo massive apoptosis at stage 7, as revealed by TUNEL staining

abnormal seminiferous tubule morphology ( J:68789 )

• mutant seminiferous tubules are devoid of mature spermatozoa

• however, mutant tubules are of normal size and contain a normal number of spermatogonia, spermatocytes, and round spermatids, with no significant changes in the size, shape or location of Leydig and Sertoli cells relative to wild-type

small testis ( J:68789 )

• mutant testes are significantly smaller than wild-type testes

arrest of spermiogenesis ( J:68789 )

• in 50% of male homozygotes, round spermatids are arrested at step 7 and fail to progress into elongated spermatids due to apoptosis

• in the remaining 50%, rare degenerating elongated spermatids fail to progress beyong stage 13

• arrest of spermiogenesis is associated with a severe reduction or absence of expression of several germ cell-specific genes that normally initiates in step 5-6 round spermatids

male infertility ( J:68789 )

• male homozygotes are completely sterile

• in constrast, female homozygotes are fertile