In the adult male, a population of diploid stem-cell spermatogonia continuously undergoes self-renewal and produces progeny cells, which initiate complex process cellular differentiation that results in mature spermatozoa. We report here stem cells isolated from testes donor male mice will repopulate sterile when injected into seminiferous tubules. Donor cell spermatogenesis recipient showed normal morpholigical characteristics produced This methodology, besides opening new avenues basic...

Spermatogenesis is a complex, highly organized, very efficient process that based upon the capacity of stem cell spermatogonia simultaneously to undergo self-renewal and provide progeny differentiate into mature spermatozoa. We report here testis-derived cells transplanted testis an infertile mouse will colonize seminiferous tubules initiate spermatogenesis in > 70% recipients. Testis-derived from newborn mice were less effective colonizing recipient testes than 5- 15- or 21- 28-day-old...

Microinjection of foreign DNA into fertilized mammalian eggs is a convenient means introducing genes the germ line. Some more important parameters that influence successful integration mouse chromosomes are described. The effects concentration, size, and form (supercoiled vs. linear with variety different ends) considered as well site injection (male pronucleus, female or cytoplasm) buffer composition. optimal conditions for entail few hundred molecules male pronucleus one-cell eggs. Under...

Spermatogonial stem cells (SSCs) self-renew and produce large numbers of committed progenitors that are destined to differentiate into spermatozoa throughout life. However, the growth factors essential for self-renewal SSCs remain unclear. In this study, a serum-free culture system transplantation assay were used identify exogenous soluble promote proliferation SSCs. Mouse pup testis enriched by selection with an anti-Thy-1 antibody cultured on STO (SIM mouse embryo-derived thioguanine...

Metallothionein-directed expression of TGF alpha in transgenic mice induced a spectrum changes the growth and differentiation certain adult tissues. First, promoted uniform epithelial hyperplasia several organs without otherwise causing major alterations tissue architecture. Second, pancreas it proliferation both acinar cells fibroblasts focally altered cell differentiation. The magnitude this response was proportional to level local, tissue-specific reproduced when placed under control...

Experiments were designed to test the effect of introns on gene expression in transgenic mice. Four different pairs constructs, which identical except that one member each pair lacked all introns, compared for mRNA after introduction into murine germ line by microinjection fertilized eggs. The two chimeric genes, made fusing either mouse metallothionein I or rat elastase 1 promoter/enhancer growth hormone gene, was assayed fetal liver pancreas, respectively, while natural an...

We inactivated the mouse metallothionein (MT)-I and MT-II genes in embryonic stem cells generated mice homozygous for these mutant alleles. These were viable reproduced normally when reared under normal laboratory conditions. They were, however, more susceptible to hepatic poisoning by cadmium. This proves that widely expressed MTs are not essential development but they do protect against cadmium toxicity. provide a means testing other proposed functions of MT vivo.

Adult liver has the unusual ability to fully regenerate after injury. Although regeneration is accomplished by division of mature hepatocytes, replicative potential these cells unknown. Here, capacity adult and their medical usefulness as donor for transplantation were investigated transfer mouse into transgenic mice that display an endogenous defect in hepatic growth function. The transplanted cell populations replaced up 80 percent diseased recipient liver. These findings demonstrate...

Although spermatogenesis is essential for reproduction, little known about spermatogonial stem cells. These cells provide the basis throughout adult life by undergoing self-renewal and providing progeny that differentiate into spermatozoa. A major impediment to our understanding of biology these inability distinguish them from spermatogonia are committed differentiation. We made use association with basement membranes transplantation assay system identify specific molecular markers on cell...

Bone marrow cells from CBA T6T6 mice and testicular teratocarcinoma 129 SvSl were transferred into blastocysts random-bred Swiss albino mice. The allowed to develop in foster mothers the adults resulting these studied for evidence of an effect cells. A total 137 resulted experiments, one that had received blastocyst stage showed several thin stripes agouti hair. All adult animals grafts skin identical those supplying In all cases which been maintained a significantly longer period than...

In a previous study we showed that genomic constructs were expressed more efficiently in transgenic mice than identical except for the lack of introns. Using mouse metallothionein promoter-rat growth hormone gene construct as model, show first intron rat is essential high-level expression, whereas other three introns are less effective. Several heterologous placed 3' coding region an intronless also ineffective. However, insertion some between promoter and improves expression. To determine...

A line of transgenic mice carrying a chimeric gene composed human insulin-like growth factor I (IGF-I) coding sequences fused to the mouse metallothionein promoter was generated study effects chronically elevated exposure IGF-I. Mice in this overexpress IGF-I most tissues studied and have circulating levels 1.5 times normal value. This results response manifested by 1.3-fold increase weight as result selective organomegaly without an apparent skeletal growth. In addition, expression...

Spermatogonial stem cells (SSCs) are responsible for maintaining spermatogenesis throughout life in the male by continuous production of daughter that differentiate into spermatozoa. However, no unique phenotypic markers to identify SSCs have been described. In this study, SSC surface phenotype was characterized using flow cytometric cell sorting conjunction with a transplantation functional assay SSCs. Highly enriched activity found MHC class I (MHC-I) – Thy-1 + c-kit fraction mouse...