Loss of connexin 43 in Sertoli cells provokes postnatal spermatogonial arrest, reduced germ cell numbers and impaired spermatogenesis.

For the reason that adult Sertoli cell specific connexin 43 knockout (SCCx43KO) mice show arrested spermatogenesis at spermatogonial level or Sertoli cell only tubules and significantly reduced germ cell (GC) numbers, the aims of the present study were (1) to characterize the remaining GC population and (2) to elucidate possible mechanisms of their fading. Apoptosis was analyzed in both, KO and wild type (WT) male littermates during postnatal development and in adulthood using TUNEL. Although GC numbers were significantly reduced in KO at 2 and 8 days postpartum (dpp) when compared to WT, no differences were found concerning apoptotic incidence between genotypes.

[Cutaneous infection with Orthopoxvirus bovis in a German Spaniel].

A 4-year-old female German Spaniel was presented with anorexia. Clinically, the dog showed papular to ulcerative lesions on the nasal planum and on the tongue. Hematological, bacteriological and mycological examinations did not contribute any evidence for the etiology of the lesions.

Detection of feline coronavirus spike gene mutations as a tool to diagnose feline infectious peritonitis.

Objectives Feline infectious peritonitis (FIP) is an important cause of death in the cat population worldwide. The ante-mortem diagnosis of FIP in clinical cases is still challenging. In cats without effusion, a definitive diagnosis can only be achieved post mortem or with invasive methods.

Loss of connexin43 (Cx43) in Sertoli cells leads to spatio-temporal alterations in occludin expression.

Within the testis, Sertoli cell (SC) junctional complexes between somatic SC create a basal and apical polarity within the seminiferous epithelium, restrict movement of molecules between cells, and separate the seminiferous epithelium into a basal and adluminal compartments. This barrier consists of membrane integrated proteins known as tight, adherens, and gap junctions, which promote cell-cell contact along the blood-testis-barrier (BTB). Nevertheless, these junctions, which form the basis of the BTB are structures whose function and dynamic regulation is still poorly understood.

Expression of the androgen receptor in the testis of mice with a Sertoli cell specific knock-out of the connexin 43 gene (SCCx43KO(-/-)).

Gap junctions are intercellular channels that connect the cytoplasm of adjacent cells, allowing the passage of small molecules (<1 kDa) and thereby the regulation of many different processes. In the male gonad, the most abundant protein that builds gap junctions is connexin 43 (Cx43, GJA1). Specific knock-out of Sertoli cells (SCCx43KO(-/-)) results in an impaired spermatogenesis up to the Sertoli cell only syndrome.

Effects of a murine germ cell-specific knockout of Connexin 43 on Connexin expression in testis and fertility.

Connexin 43 (Cx 43)--expressed by germ cells (GC), Sertoli cells (SC) and Leydig cells--is one of at least eleven Cx in the murine testis. A general knockout (KO) of Cx 43 in mice results in perinatal death and a SC-specific KO of Cx 43 (SCCx43KO) causes infertility of male mice by preventing the initiation of spermatogenesis. To further elucidate the role of Cx 43 in the testis, a new mouse model with a GC-specific KO of Cx 43 (GCCx43KO) was created by using the Cre/loxP recombination system.

Sertoli-cell-specific knockout of connexin 43 leads to multiple alterations in testicular gene expression in prepubertal mice.

A significant decline in human male reproductive function has been reported for the past 20 years but the molecular mechanisms remain poorly understood. However, recent studies showed that the gap junction protein connexin-43 (CX43; also known as GJA1) might be involved. CX43 is the predominant testicular connexin (CX) in most species, including in humans.

Altered differentiation and clustering of Sertoli cells in transgenic mice showing a Sertoli cell specific knockout of the connexin 43 gene.

Histological analysis revealed that Sertoli cell specific knockout of the predominant testicular gap junction protein connexin 43 results in a spermatogenic arrest at the level of spermatogonia or Sertoli cell-only syndrome, intratubular cell clusters and still proliferating adult Sertoli cells, implying an important role for connexin 43 in the Sertoli and germ cell development. This study aimed to determine the (1) Sertoli cell maturation state, (2) time of occurrence and (3) composition, differentiation and fate of clustered cells in knockout mice. Using immunohistochemistry connexin 43 deficient Sertoli cells showed an accurate start of the mature markers androgen receptor and GATA-1 during puberty and a vimentin expression from neonatal to adult.

Major involvement of connexin 43 in seminiferous epithelial junction dynamics and male fertility.

In different epithelia, cell membranes contacting one another form intercellular junctional complexes including tight, adherens and gap junctions, which could mutually influence the expression of each other. We have here investigated the role of Cx43 in the control of adherens and tight junction proteins (N-cadherin, beta-catenin, occludin and ZO-1) by using conditional Sertoli cell knockout Cx43 (SCCx43KO(-/-)) transgenic mice and specific anti-Cx43 siRNA. Gap junction coupling and Cx43 levels were reduced in SCCx43KO(-/-) as compared to Wild-type testes.