A zinc finger truncation of murine WT1 results in the characteristic urogenital abnormalities of Denys-Drash syndrome. (1/850)

The Wilms tumor-suppressor gene, WT1, plays a key role in urogenital development, and WT1 dysfunction is implicated in both neoplastic (Wilms tumor, mesothelioma, leukemias, and breast cancer) and nonneoplastic (glomerulosclerosis) disease. The analysis of diseases linked specifically with WT1 mutations, such as Denys-Drash syndrome (DDS), can provide valuable insight concerning the role of WT1 in development and disease. DDS is a rare childhood disease characterized by a nephropathy involving mesangial sclerosis, XY pseudohermaphroditism, and/or Wilms tumor (WT). DDS patients are constitutionally heterozygous for exonic point mutations in WT1, which include mutations predicted to truncate the protein within the C-terminal zinc finger (ZF) region. We report that heterozygosity for a targeted murine Wt1 allele, Wt1(tmT396), which truncates ZF3 at codon 396, induces mesangial sclerosis characteristic of DDS in adult heterozygous and chimeric mice. Male genital defects also were evident and there was a single case of Wilms tumor in which the transcript of the nontargeted allele showed an exon 9 skipping event, implying a causal link between Wt1 dysfunction and Wilms tumorigenesis in mice. However, the mutant WT1(tmT396) protein accounted for only 5% of WT1 in both heterozygous embryonic stem cells and the WT. This has implications regarding the mechanism by which the mutant allele exerts its effect.  (+info)

The Drosophila Bruton's tyrosine kinase (Btk) homolog is required for adult survival and male genital formation. (2/850)

We isolated a Drosophila fickleP (ficP) mutant with a shortened copulatory duration and reduced adult-stage life span. The reduced copulatory duration is ascribable to incomplete fusion of the left and right halves of the apodeme that holds the penis during copulation. ficP is an intronic mutation occurring in the Btk gene, a gene which encodes two forms (type 1 and type 2) of a Bruton's tyrosine kinase (Btk) family cytoplasmic tyrosine kinase as a result of alternative exon usage. The ficP mutation prevents the formation of the type 2 isoform but leaves expression of the type 1 transcript intact. Ubiquitous overexpression of the wild-type cDNA by using a heat shock 70 promoter during the late larval or pupal stages rescued the life span and genital defects in the mutant, respectively, establishing the causal relationship between the ficP phenotypes and the Btk gene mutation. The stage specificity of the rescuing ability suggests that the Btk gene is required for the development of male genitalia and substrates required for adult survival.  (+info)

Influence of capacitation and fluids from the male and female genital tract on the zona binding ability of bull spermatozoa. (3/850)

Before fertilization, inseminated spermatozoa acquire the ability to fertilize an egg, a phenomenon called capacitation. Bovine sperm capacitation is influenced by factors originating from both the male and female genital tract, and results in intracellular and membrane changes of the spermatozoa that facilitate the induction of the acrosome reaction. However, the effects of reproductive tract secretions and capacitation on the binding of spermatozoa to the zona pellucida have not been investigated. In this study, a sperm-egg binding assay was used to determine whether the ability of bull spermatozoa to bind to the zona pellucida was altered during in vitro capacitation by heparin or oviductal fluid, or by treatment of spermatozoa from the cauda epididymidis with accessory sex gland fluid. In addition, biotinylated solubilized zona pellucida proteins were used to visualize zona binding on spermatozoa. The ability of bull spermatozoa to bind to the zona pellucida was increased after both heparin and oviductal fluid induced in vitro capacitation. Exposure of spermatozoa from the cauda epididymidis to accessory sex gland fluid resulted in a direct increase in zona binding ability, followed by a further increase during capacitation in vitro. Binding of solubilized zona proteins was restricted to the acrosomal cap of bull spermatozoa. It is suggested that the observed increased ability of bull spermatozoa to bind to the zona pellucida enables optimal sperm-egg attachment, which also relates to the induction of the acrosome reaction by the zona pellucida. Thus, increased zona binding ability is likely to be an essential part of the process of capacitation.  (+info)

Apc1638T: a mouse model delineating critical domains of the adenomatous polyposis coli protein involved in tumorigenesis and development. (4/850)

The adenomatous polyposis coli (APC) gene is considered as the true gatekeeper of colonic epithelial proliferation: It is mutated in the majority of colorectal tumors, and mutations occur at early stages of tumor development in mouse and man. These mutant proteins lack most of the seven 20-amino-acid repeats and all SAMP motifs that have been associated with down-regulation of intracellular beta-catenin levels. In addition, they lack the carboxy-terminal domains that bind to DLG, EB1, and microtubulin. APC also appears to be essential in development because homozygosity for mouse Apc mutations invariably results in early embryonic lethality. Here, we describe the generation of a mouse model carrying a targeted mutation at codon 1638 of the mouse Apc gene, Apc1638T, resulting in a truncated Apc protein encompassing three of the seven 20 amino acid repeats and one SAMP motif, but missing all of the carboxy-terminal domains thought to be associated with tumorigenesis. Surprisingly, homozygosity for the Apc1638T mutation is compatible with postnatal life. However, homozygous mutant animals are characterized by growth retardation, a reduced postnatal viability on the B6 genetic background, the absence of preputial glands, and the formation of nipple-associated cysts. Most importantly, Apc1638T/1638T animals that survive to adulthood are tumor free. Although the full complement of Apc1638T is sufficient for proper beta-catenin signaling, dosage reductions of the truncated protein result in increasingly severe defects in beta-catenin regulation. The SAMP motif retained in Apc1638T also appears to be important for this function as shown by analysis of the Apc1572T protein in which its targeted deletion results in a further reduction in the ability of properly controlling beta-catenin/Tcf signaling. These results indicate that the association with DLG, EB1, and microtubulin is less critical for the maintenance of homeostasis by APC than has been suggested previously, and that proper beta-catenin regulation by APC appears to be required for normal embryonic development and tumor suppression.  (+info)

Sex difference in target seeking behavior of developing cremaster muscles and the resulting first visible sign of somatic sexual differentiation in marsupial mammals. (5/850)

Cremaster muscles are present in both male and female developing and adult marsupial mammals. They are complex structures and composed of several distinct bundles of striated muscle fibers provided with: (1) a distinct and extensive innervation; (2) a distinct blood vascular supply; (3) a distinct tendineous origin on the anterosuperior iliac spine; and (4) distinct target structures. The muscles thus seem to be separate anatomical entities and not a part of one or more of the layers of the ventral abdominal wall musculature. Cremaster muscles in males are elongated, are larger than in females, and for the most part are a component of the funiculus spermaticus. They insert on the distal part of the tunica vaginalis. The distal parts of the muscles in females are flattened ("fan shaped") and insert over a broad area on the dorsal borders of the mammary glands. Muscles in males have no relation whatsoever to the male mammary glandular rudiments. Muscles in females are attached at the base of the uterine round ligament. The remarkable sex difference in target structures of marsupial cremaster muscles becomes noticeable during perinatal life when outgrowing muscles take a different path in males and females. The initial appearance of this sexually dimorphic trait precedes the sexual differentiation of the genital ducts and external genitalia. In fetal males, the cremaster muscles grow in the direction of the site where scrotal bulges initially appear in the subcutaneous layers and later on the inguinal skin surface. They also take the gubernacular core of the ventral abdominal wall and the attached peritoneal epithelium with them during this outgrowth process. Consequently, this results in the development of a slitlike evagination of the abdominal lumen as the primary step to development of the processus vaginalis, while the testis and adjacent mesonephros and its duct are still attached to the posterior abdominal wall. In fetal females, the outgrowing cremaster muscles pass along the gubernacular core and, subsequently, this structure develops further as the tip (attached to the tubo-uterine junction) of the intra-abdominally protruding and further developing uterine round ligament. The female cremaster muscles grow further into caudal direction to shape a dorsal border of the developing mammary glands. The early onset of this sexually dimorphic outgrowth of cremaster muscles indicates that the "classical hormones" of sexual differentiation (anti-Mullerian hormone [AMH] and steroidal androgens) are not involved in this process. It could thus depend on primary genetic control with male development associated with the male-limited activity of genes on the Y-chromosomes and female development as the default process. Alternatively, the process in males could be under the control of an as yet unidentified third fetal testicular hormone involved in sexual differentiation processes which must then show an unexpectely early (i.e., perinatal) onset of its secretion.  (+info)

Monodactylous limbs and abnormal genitalia are associated with hemizygosity for the human 2q31 region that includes the HOXD cluster. (6/850)

Vertebrates have four clusters of Hox genes (HoxA, HoxB, HoxC, and HoxD). A variety of expression and mutation studies indicate that posterior members of the HoxA and HoxD clusters play an important role in vertebrate limb development. In humans, mutations in HOXD13 have been associated with type II syndactyly or synpolydactyly, and, in HOXA13, with hand-foot-genital syndrome. We have investigated two unrelated children with a previously unreported pattern of severe developmental defects on the anterior-posterior (a-p) limb axis and in the genitalia, consisting of a single bone in the zeugopod, either monodactyly or oligodactyly in the autopod of all four limbs, and penoscrotal hypoplasia. Both children are heterozygous for a deletion that eliminates at least eight (HOXD3-HOXD13) of the nine genes in the HOXD cluster. We propose that the patients' phenotypes are due in part to haploinsufficiency for HOXD-cluster genes. This hypothesis is supported by the expression patterns of these genes in early vertebrate embryos. However, the involvement of additional genes in the region could explain the discordance, in severity, between these human phenotypes and the milder, non-polarized phenotypes present in mice hemizygous for HoxD cluster genes. These cases represent the first reported examples of deficiencies for an entire Hox cluster in vertebrates and suggest that the diploid dose of human HOXD genes is crucial for normal growth and patterning of the limbs along the anterior-posterior axis.  (+info)

Detection of human papillomavirus types 6 and 11 in pubic and perianal hair from patients with genital warts. (7/850)

Genital human papillomavirus (HPV) types 6 and 11 are of clinical importance due to their role in the development of anogenital warts. A pilot study was performed to investigate whether DNAs from HPV types 6 and 11 are present in hairs plucked from the pubic and perianal regions and eyebrows of patients with genital warts at present and patients with a recent history of genital warts. Genital HPV DNA was detected in 9 of 25 (36%) pubic hair samples and in 11 of 22 (50%) perianal hair samples by the CPI/CPIIg PCR. After sequencing of 17 of 20 samples, HPV type 6 or 11 was detected in 6 of 25 (24%) hair samples from the pubis and 8 of 22 (36%) hair samples from the perianal region. These types were not detected in plucked eyebrow hairs. In contrast, the HPV types associated with epidermodysplasia verruciformis were detected in similar proportions (62%) in both samples of pubic and eyebrow hairs. Moreover, HPV type 6 and 11 DNAs were detected in pubic hairs plucked from two patients who had been successfully treated and who did not show any lesion at the time of hair collection; this finding is an argument that HPV DNA may persist in this region. The presence of genital HPV types in plucked pubic and perianal hair suggests that there is an endogenous reservoir for HPV which may play a role in the recurrences of genital warts.  (+info)

The sonographic identification of fetal gender from 11 to 14 weeks of gestation. (8/850)

OBJECTIVE: To determine the feasibility of correctly identifying fetal gender from 11 to 14 weeks' gestation. METHODS: A prospective cross-sectional study in a university Department of Obstetrics and Gynaecology, London. A total of 524 women from an unselected population underwent a detailed assessment of fetal anatomy at 11-14 weeks of gestation (confirmed by crown-rump length) by means of transabdominal sonography, and transvaginal sonography (26%) when necessary. Fetal gender was identified in the transverse and sagittal planes, and was confirmed at birth. RESULTS: The overall success of correctly assigning fetal gender increased with gestational age from 46% to 75%, 79% and 90% at 11, 12, 13 and 14 weeks, respectively. The ability of the operator to assign fetal gender significantly improved with increasing gestational age (p < 0.0001), being 59%, 87%, 92% and 98% at 11, 12, 13 and 14 weeks, respectively. The accuracy of correctly identifying fetal gender when attempted did not change with gestational age. Fetal gender or the performance of the scan by different operators did not affect the results. CONCLUSION: Whilst the accuracy of sonographic determination of fetal gender at 11-14 weeks is good, it still falls significantly short of invasive karyotyping tests.  (+info)