Ehd4 is required to attain normal prepubertal testis size but dispensable for fertility in male mice

Abstract

The four highly homologous members of the C-terminal EH domain-containing (EHD) protein family (EHD1-4) regulates endocytic recycling. To delineate the role of EHD4 in normal physiology and development, mice with a conditional knockout of the Ehd4 gene were generated. PCR of genomic DNA and Western blotting of organ lysates from Ehd4 −/− mice confirmed EHD4 deletion. Ehd4 −/− mice were viable and born at expected Mendelian ratios; however, males showed a 50% reduction in testis weight, obvious from postnatal day 31. An early (day 10) increase in germ cell proliferation and apoptosis and a later increase in apoptosis (day 31) were seen in the Ehd4 −/− testis. Other defects included a progressive reduction in seminiferous tubule diameter, dysregulation of seminiferous epithelium and head abnormalities in elongated spermatids. As a consequence, lower sperm counts and reduced fertility were observed in Ehd4 −/− males. Interestingly, EHD protein expression was seen to be temporally regulated in the testis andCorrespondence and requests for materials should be addressed to Dr. Hamid Band (hband@unmc.edu) or Dr. Mayumi Naramura (mnaramura@unmc.edu).. NIH Public Access Author ManuscriptGenesis. Author manuscript; available in PMC 2011 May 1. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript levels peaked between days 10 and 15. In the adult testis, EHD4 was highly expressed in primary spermatocytes and EHD4 deletion altered the levels of other EHD proteins in an age-dependent manner. We conclude that high levels of EHD1in the adult Ehd4 −/− testis functionally compensate for lack of EHD4 and prevents the development of severe fertility defects. Our results suggest a role for EHD4 in the proper development of post-mitotic and post-meiotic germ cells and implicate EHD protein-mediated endocytic recycling as an important process in germ cell development and testis function.

The Magea gene cluster regulates male germ cell apoptosis without affecting the fertility in mice

“…1C). Similar phenotypes, such as small testes but normal fertility or sperm count, have been reported in mice with targeted deletions of gene members from the C-terminal EH domain-containing (EHD) protein family (EHD4)45, the Pumilio gene family (Pum2)46, the protein inhibitor of activated STAT (PIASx) family47, and the cytochrome c family48. In addition, other mouse models with gene cluster deletions, such as deletions of the Dickkopf (DKK) family49, the testicular haploid expressed gene (Theg) family50, and the ADP-ribosylation factor (ARF) family51, have shown that specific gene members are dispensable for development or fertility.…”

EHD proteins: key conductors of endocytic transport

“…Consistent with these findings, a recent study demonstrated involvement of EHD3 in EE-to-Golgi retrograde transport aberrant Golgi morphology, function, and delayed biosynthetic transport of lysosomal enzymes [29]. On the other hand, the modest phenotypes described for EHD1 knock-down mice [30, 31] suggest that with 86% identity to EHD1, EHD3 may be highly functionally redundant with EHD1 in most tissues. Ultimately, the generation of double knock-out mice will be key to determining the degree of EHD1/EHD3 functional redundancy.…”

“…More recently, an additional EHD1 mouse model demonstrated that EHD1 expression is required for normal spermatogenesis and fertility of male mice [32], consistent with the fly phenotype. It is noteworthy that loss of the EHD1 paralogue and oligomerisation partner, EHD4, is not necessary for male mouse fertility, but is needed to allow testis development to normal size [31]. Plants such as Arabidopsis thaliana also have homologues of EHD proteins (AtEHD1 and At EHD2), [65], and studies point to a role for these proteins in regulating endocytosis and signaling [66, 67].…”

CSF-1 receptor signalling is governed by pre-requisite EHD1 mediated receptor display on the macrophage cell surface

“…We have found that EHD1 deletion on a mixed C57BL/6 and 129Sv background is partially penetrant embryonic lethal and associated with defective spermatogenesis and lens developmental defects, while it is fully embryonic lethal on a predominantly C57BL/6 background [35–37]. Here, we use primary bone marrow-derived macrophages (BMDMs) with inducible EHD1-Knockout (EHD1-KO) capacity, to study the biological and physiological function of EHD1 in macrophages.…”