The polycystic kidney disease 1 (PKD1) gene encodes a novel protein with multiple cell recognition domains.

Characterization of the polycystic kidney disease 1 (PKD1) gene has been complicated by genomic rearrangements on chromosome 16. We have used an exon linking strategy, taking RNA from a cell line containing PKD1 but not the duplicate loci, to clone a cDNA contig of the entire transcript. The transcript consists of 14,148 bp (including a correction to the previously described C terminus), distributed among 46 exons spanning 52 kb. The predicted PKD1 protein, polycystin, is a glycoprotein with multiple transmembrane domains and a cytoplasmic C-tail. The N-terminal extracellular region of over 2,500 aa contains leucine-rich repeats, a C-type lectin, 16 immunoglobulin-like repeats and four type III fibronectin-related domains. Our results indicate that polycystin is an integral membrane protein involved in cell-cell/matrix interactions.

Regulation of pre-T cell receptor (pT alpha-TCR beta) gene expression during human thymic development.

In murine T cell development, early thymocytes that productively rearrange the T cell receptor (TCR) beta locus are selected to continue maturation, before TCR alpha expression, by means of a pre-TCR alpha- (pT alpha-) TCR beta heterodimer (pre-TCR). The aim of this study was to identify equivalent stages in human thymocyte development. We show here that variable-diversity-joining region TCR beta rearrangement and the expression of full-length TCR beta transcripts have been initiated in some immature thymocytes at the TCR alpha/beta- CD4+CD8- stage, and become common in a downstream subset of TCR alpha/beta- CD4+CD8+ thymocytes that is highly enriched in large cycling cells. TCR beta chain expression was hardly detected in TCR alpha/beta- CD4+CD8- thymocytes, whereas cytoplasmic TCR beta chain was found in virtually all TCR alpha/beta- CD4+CD8+ blasts. In addition, a TCR beta complex distinct from the mature TCR alpha/beta heterodimer was immunoprecipitated only from the latter subset. cDNA derived from TCR alpha/beta- CD4+CD8+ blasts allowed us to identify and clone the gene encoding the human pT alpha chain, and to examine its expression at different stages of thymocyte development. Our results show that high pT alpha transcription occurs only in CD4+CD8- and CD4+CD8+ TCR alpha/beta- thymocytes, whereas it is weaker in earlier and later stages of development. Based on these results, we propose that the transition from TCR alpha/beta- CD4+CD8- to TCR alpha/beta- CD4+CD8+ thymocytes represents a critical developmental stage at which the successful expression of TCR beta promotes the clonal expansion and further maturation of human thymocytes, independent of TCR alpha.

Paget's disease of bone: evidence for a susceptibility locus on chromosome 18q and for genetic heterogeneity.

Paget's disease of bone is a common condition characterized by bone pain, deformity, pathological fracture, and an increased incidence of osteosarcoma. Genetic factors play a role in the pathogenesis of Paget's disease but the molecular basis of the disease remains unclear. Previous genetic linkage studies have mapped the rare Paget's disease-like bone dysplasia familial expansile osteolysis (FEO) to chromosome 18q21-22, and recent work has shown evidence of linkage between this locus and Paget's disease in one family. Here we studied the relationship between the 18q21-22 locus and Paget's disease in eight large multiplex families from diverse ethnic backgrounds with inherited Paget's disease. Paget's disease was inherited as an autosomal dominant trait in all families, with high penetrance by the sixth decade. Analysis of seven highly polymorphic markers from chromosome 18q21-22 showed positive summated two-point log10 odds ratio (lodscores) of +2.97 with the marker D18S42 at a recombination fraction (theta) = 0.05, and of +2.95 with the marker D18S60 at theta = 0.00, values which are close to the cut-off of +3.0, which is generally accepted as evidence of linkage. Segregation analysis of the haplotypes and formal statistical analysis using the HOMOG program provided evidence for genetic heterogeneity, however, with evidence for linkage in five families and against linkage in the remaining three families (chi square 8.82; df = 2; p < 0.025). Multipoint linkage analysis in the five linked families showed lodscores of above +3.5 across the whole susceptibility region and a maximum summated lodscore of 3.89 at the marker D18S465. In the three nonlinked families, negative multipoint results were obtained for the whole region, with lodscores below -2.0 in one family, excluding this as a candidate locus for the disease. Our studies demonstrate the importance of hereditary factors in the pathogenesis of Paget's disease and confirm evidence of linkage between Paget's disease and chromosome 18q21-22 in some families. This raises the possibility that Paget's disease and FEO may share a common molecular basis, perhaps due to different mutations in the same gene or family of genes. Data from three families did not support evidence of linkage to 18q21-22 however, indicating that Paget's disease is genetically heterogeneous and suggests the presence of at least one additional locus which remains to be discovered.

The role of the CAG repeat polymorphism in the androgen receptor gene and of skewed X-chromosome inactivation, in the pathogenesis of hirsutism.

The human androgen receptor (AR) gene contains a variable number of CAG repeats within exon 1. Shorter AR alleles, by increasing transactivation, may result in augmented AR-mediated sensitivity of the hair follicle. We have evaluated whether the number of CAG repeats, or if skewed inactivation of X-chromosome, favoring the presence of shorter AR alleles, influence hirsutism in women with and without hyperandrogenemia. Twenty-eight women with idiopathic hirsutism (normal serum androgens), 34 women with hyperandrogenic hirsutism (increased serum androgens), and 15 healthy control women were analyzed by evaluating the number of CAG repeats in genomic DNA, as well as the methylation pattern (after DNA digestion with HpaII), which allows identification of which allele is inactive. Despite marked differences among the groups in serum androgens, which were markedly increased in women with hyperandrogenic hirsutism as compared with women with idiopathic hirsutism and to controls, there were no significant differences among the groups in the number of CAG repeats. Moreover, skewed X-chromosome inactivation was found in 10 subjects (3 with idiopathic hirsutism, 5 with hyperandrogenic hirsutism, and 2 controls; P = 0.746) of the 67 women (14.9%) who were heterozygous for the AR gene. In several of these subjects, it was the shorter allele that was preferentially inactivated. In conclusion, neither the CAG repeat polymorphism in the AR gene, nor skewed X-chromosome inactivation, seem to play a significant role in the pathogenesis of hirsutism.

TNF-alpha and hyperandrogenism: a clinical, biochemical, and molecular genetic study.

To evaluate the role of TNF-alpha in the pathogenesis of hyperandrogenism, we have evaluated the serum TNF-alpha levels, as well as several polymorphisms in the promoter region of the TNF-alpha gene, in a group of 60 hyperandrogenic patients and 27 healthy controls matched for body mass index. Hyperandrogenic patients presented with mildly increased serum TNF-alpha levels as compared with controls (mean[median] +/- SD: 7.2[7.0] +/- 3.3 pg/ml vs. 5.6[4.4] +/- 4.0 pg/ml, P < 0.02). Although no differences in body mass index and insulin resistance indexes were observed between patients and controls, when subjects were classified by body weight, serum TNF-alpha was increased only in lean patients as compared with lean controls, but this difference was not statistically significant when comparing obese patients with obese controls. The TNF-alpha gene polymorphisms studied here (-1196C/T, -1125G/C, -1031T/C, -863C/A, -857C/T, -316G/A, -308G/A, -238G/A, and -163G/A) were equally distributed in hyperandrogenic patients and controls. However, carriers of the -308A variant presented with increased basal and leuprolide-stimulated serum androgens and 17-hydroxyprogesterone levels when considering patients and controls as a group. No differences were observed in serum TNF-alpha levels, body mass index, and insulin resistance indexes, depending on the presence or absence of these variants. In conclusion, our present results suggest that the TNF-alpha system might contribute to the pathogenesis of hyperandrogenism, independent of obesity and insulin resistance. However, elucidation of the precise mechanisms underlying the relationship between the TNF-alpha system and androgen excess is needed before considering TNF-alpha as a significant contributing factor to the development of hyperandrogenism.

A prospective study of the prevalence of the polycystic ovary syndrome in unselected Caucasian women from Spain.

We prospectively estimated the prevalence of the polycystic ovary syndrome (PCOS), as defined by the NIH/NICHHD 1990 endocrine criteria, in a population of 154 Caucasian women of reproductive age reporting spontaneously for blood donation. Anthropometric data; the presence of hirsutism, acne, and androgenic alopecia; and the menstrual history were recorded by a single investigator. In 145 women, blood samples were also obtained for measurement of serum androgen levels. PCOS was defined by the presence of 1) oligomenorrhea, 2) clinical and/or biochemical hyperandrogenism, and 3) exclusion of hyperprolactinemia, thyroid disorders, and nonclassic 21-hydroxylase deficiency. Hirsutism was defined by a modified Ferriman-Gallwey score of 8 or more, acne was considered as a sign of hyperandrogenism when persistent after the second decade of life, and hyperandrogenemia was defined by an increase in circulating testosterone or dehydroepiandrosterone sulfate or an increase in the free androgen index above the 95th percentile of the control values derived from the nonhirsute, nonacneic women having regular menses who were not receiving hormonal therapy. PCOS was present in 10(6.5%), hirsutism was present in 11 (7.1%), and acne was present in 19 (12.3%) of the 154 women. Our results demonstrate a 6.5% prevalence of PCOS, as defined, in a minimally biased population of Caucasian women from Spain. The polycystic ovary syndrome, hirsutism, and acne are common endocrine disorders in women.

Screening for mutations in the steroidogenic acute regulatory protein and steroidogenic factor-1 genes, and in CYP11A and dosage-sensitive sex reversal-adrenal hypoplasia gene on the X chromosome, gene-1 (DAX-1), in hyperandrogenic hirsute women.

Abstract Abnormalities in adrenal and/or ovarian steroidogenesis are found in most patients with hirsutism. The rate-limiting step in the synthesis of steroids in the ovary and the adrenal is the conversion of cholesterol into pregnenolone by cholesterol side-chain cleavage enzyme (P450scc), encoded by the gene CYP11A, after cholesterol is introduced into the mitochondria by the steroidogenic acute regulatory protein (StAR). DAX-1 is a repressor of StAR gene expression, and steroidogenic factor-1 (SF-1) is a regulator of CYP11A, DAX-1, and StAR gene. Mutations in any of these factors resulting in gain of function, or loss of repression, of StAR or P450scc might contribute to the steroidogenic abnormalities present in hirsute patients. In the present study we have screened, using heteroduplex analysis, the genes encoding StAR and SF-1 as well as DAX-1 and CYP11A for mutations in genomic DNA from 19 women presenting with hirsutism and increased serum androgen levels. When variants were found, analysis was extended to a larger group of hyperandrogenic patients and nonaffected women. Two variants were identified in the SF-1 gene. A G-->C change in exon 6, resulting in an Arg(365)Pro mutation, was found in 1 of 45 patients, but not in controls. Also, a Gly(146)Ala missense mutation, resulting from a G-->C change in exon 4, was found in 2 of 48 patients and in 2 of 50 nonaffected individuals. We identified a C-->T base pair change at position -33 of the StAR gene. Three of 48 patients and 3 of 43 controls presented this variant. No mutations were found in coding regions of the StAR gene. Analysis of CYP11A-coding regions identified a G-->A change in exon 3, resulting in a Val(179)Ile missense mutation. This mutation was found in 1 of 29 patients studied and was not present in 50 controls. Finally, analysis of DAX-1 showed no variant in any of the women studied. In conclusion, mutations in StAR, SF-1, CYP11A, and DAX-1 are seldom found in hirsute patients and do not explain the steroidogenic abnormalities found in these women.

Isolation of microsatellites from the spinal muscular atrophy (SMA) candidate region on chromosome 5q and linkage analysis in Spanish SMA families.

A locus responsible for autosomal recessive spinal muscular atrophy (SMA) on chromosome 5q11.2-q13.3 has been mapped to a critical interval delimited by markers D5S435 and D5S557. By a modification of the Vectorette-(GT)n method, we have isolated three polymorphic CA repeats from two YACs of the SMA region. Two of them (D5S1417 and D5S1416) map within the SMA critical region, and the other (D5S1415) is centromeric to D5S435. Linkage analysis in Spanish SMA families with eleven markers showed that in our families the disease is linked to this region and confirmed that the novel markers are tightly linked to the SMA locus. The most likely order of markers was 5cen-(D5S63/D5S1356)-(D5S125/D5S465)- (D5S435/D5S1417/D5S1416/D5S557)-D5S610- D5S112-D5S127-5qter, with odds against alternative orders > 1,000:1. Genetic distances are in agreement with those previously published. However, the recombination fraction between D5S610 and D5S112 is remarkably greater than expected from the physical distance, suggesting a hot spot for recombination in this region. Our results from haplotype and multipoint analyses show that the SMA locus must lie between D5S465 and D5S112, and lend further support to the current location of the SMA locus.

Receiver operating characteristic analysis of the performance of basal serum hormone profiles for the diagnosis of polycystic ovary syndrome in epidemiological studies.

OBJECTIVE: We have used receiver operating characteristic (ROC) analysis to determine the diagnostic performance of several serum parameters, in order to evaluate their potential usefulness in establishing the diagnosis of polycystic ovary syndrome (PCOS) in epidemiological studies. DESIGN: Prospective study. METHODS: One hundred and fourteen women reporting spontaneously for blood donation were included in the study. Menopausal and oral contraceptive-treated women were excluded. Serum samples were obtained at the moment of donation, independently of fasting, time of day or day of menstrual cycle. Measurements included total testosterone, sex hormone-binding globulin (SHBG), dehydroepiandrosterone sulfate (DHEAS), LH, FSH and estradiol. The free testosterone (FT) concentration and the free androgen index (FAI) were calculated from testosterone and SHBG levels. ROC curves were calculated for all these serum determinations. RESULTS: Eight patients were diagnosed with PCOS, according to the presence of oligomenorrhea, hirsutism, acne and/or hyperandrogenemia, and exclusion of non-classic congenital adrenal hyperplasia, hypothyroidism and hyperprolactinemia. Of the parameters studied SHBG, FAI, FT and DHEAS were considered adequate measures for the diagnosis of PCOS. For example, serum SHBG levels showed an area under the ROC curve of 0.875+/-(S.E.(w))0.045 (95% confidence interval 0.800-0.929). A SHBG decision threshold <37 nmol/l had a sensitivity of 87.5%, a specificity of 86.8%, a positive likelihood ratio of 6.63, and a negative likelihood ratio of 0.14, for the diagnosis of PCOS. CONCLUSIONS: Our present results strongly suggest that decreased SHBG levels, and increased FAI, free testosterone concentration and DHEAS concentrations, are highly effective as single analytical procedures in epidemiological studies for the detection of PCOS in women of reproductive age.

The presence of the 21-hydroxylase deficiency carrier status in hirsute women: phenotype-genotype correlations.

OBJECTIVE: To determine the role of heterozygosity for mutations in the 21-hydroxylase gene (CYP21) in the pathogenesis of hyperandrogenism. DESIGN: Controlled clinical study. SETTING: Tertiary care institutional hospital. PATIENT(S): Forty hirsute women and 13 healthy control women. INTERVENTION(S): The source of androgen excess was determined by the changes in serum testosterone levels in response to a single 3.75-mg i.m. dose of triptorelin. MAIN OUTCOME MEASURE(S): CYP21 molecular genetic analysis and serum 17-hydroxyprogesterone levels. RESULT(S): Eight patients and one control were heterozygous carriers of CYP21 mutations. Two patients with adrenal hyperandrogenism and one patient with ovarian hyperandrogenism, who carried the V281L mutation had an increased ACTH-stimulated 17-hydroxyprogesterone level (>4.1 ng/mL) that persisted during gonadal suppression. Another patient with adrenal hyperandrogenism carried the V281L mutation, and her ACTH-stimulated 17-hydroxyprogesterone level was elevated only during gonadal suppression. Four patients (three with idiopathic hirsutism, one with ovarian hyperandrogenism) and one control were carriers of CYP21 mutations typically associated with classic congenital adrenal hyperplasia but had normal basal and ACTH-stimulated 17-hydroxyprogesterone levels. Nine patients without CYP21 mutations had increased ACTH-stimulated 17-hydroxyprogesterone levels; these decreased to normal in six of the patients during gonadal suppression. CONCLUSION(S): The response of serum 17-hydroxyprogesterone to ACTH does not predict CYP21 carrier status. No clear concordance was found between the CYP21 genotype and the functional origin of androgen excess.

Role of the pentanucleotide (tttta)(n) polymorphism in the promoter of the CYP11a gene in the pathogenesis of hirsutism.

OBJECTIVE: To determine if the (tttta)(n) repeat polymorphism in the promoter region of CYP11a gene is associated with hirsutism and hyperandrogenism in women from Spain. DESIGN: Controlled clinical study. SETTING: Tertiary-care institutional hospital. PATIENT(S): Ninety-two hirsute women and 33 healthy control women. INTERVENTION(S): Basal and adrenocorticotropin-stimulated serum samples and genomic DNA extracted and purified from whole-blood samples were obtained during the follicular phase of the menstrual cycle. MAIN OUTCOME MEASURE(S): CYP11a (tttta)(n) repeat-polymorphism genotype and serum ovarian and adrenal androgen levels. RESULT(S): None of the CYP11a (tttta)(n) polymorphic alleles was associated with hirsutism. The absence of the four-repeat-units allele (4R-- genotype), which has been reported by other authors to be associated with polycystic ovary syndrome (PCOS), was found in 22.4% of the women studied here and was equally distributed among patients and controls, independently of the presence of PCOS and/or ovarian or adrenal hyperandrogenism. No differences were observed in serum hormone concentrations in 4R-- individuals as compared with subjects with at least one four-repeat-units allele. CONCLUSION(S): The (tttta)(n) repeat polymorphism in the promoter region of CYP11a does not appear to play any significant role in the pathogenesis of hirsutism and hyperandrogenism in women from Spain.

Role of the follistatin gene in women with polycystic ovary syndrome.

OBJECTIVE: To search for mutations in the coding exons of the follistatin gene of women diagnosed with polycystic ovary syndrome (PCOS). DESIGN: Controlled clinical study. SETTING: Tertiary institutional hospital. PATIENT(S): Thirty-four women diagnosed with PCOS and 15 healthy control women. INTERVENTION(S): Whole blood and serum samples were collected during the follicular phase of the menstrual cycle. MAIN OUTCOME MEASURE(S): Circulating total testosterone (T), sex hormone-binding globulin (SHBG), calculated free T (FT), androstenedione (A), dehydroepiandrosterone-sulfate (DHEAS), LH, FSH, E2, and basal and adenocorticotropic hormone (ACTH)-stimulated 17-hydroxyprogesterone (17-OHP) were determined. Insulin resistance was estimated from fasting glucose and insulin levels, using the homeostasis model assessment. The coding regions of the follistatin gene were studied by heteroduplex analysis after polymerase chain reaction amplification. RESULT(S): Women with PCOS presented with higher body-mass index, insulin resistance, T, FT, A, and ACTH-stimulated 17-OHP serum concentrations and lower SHBG serum levels, as compared with controls. No differences were observed among the groups in serum DHEAS, basal 17-OHP, E(2), LH, and FSH. No mutations were found in coding regions of the follistatin gene, with the exception of a G to A change at cDNA position 951, resulting in a silent mutation. This change was present in 2 (5.9%) of 34 patients and 1 (6.7%) of 15 controls. CONCLUSION(S): Mutations in the coding regions of the follistatin gene do not appear to be related to PCOS.

[Heterozygosity loss and somatic mutations in type I and II dominant autosomal renal polycystic kidney disease: evidence of a recessive mechanism at a cell level in cystogenesis]. / Estudio de pérdidas de heterozigosidad y mutaciones somáticas en la poliquistosis renal autosómica dominante tipos I y II: demostración de un mecanismo recesivo a nivel celular en la cistogénesis.

Autosomal dominant polycystic kidney disease (ADPKD) is a systemic disorder mainly characterized by renal cyst formation. Cysts in ADPKD are focal in nature, since only a small fraction of nephrons become cystic. The hypothesis that a second hit may be required for cyst formation has been proposed. This hypothesis suggests that inactivation of the inherited wild-type allele by a somatic mutation triggers cyst formation. In some cases, this second hit eliminates the normal allele and the affected cells remain with a single allele, which is the inherited mutated copy, and we only visualize one allele after the amplification by polymerase chain reaction; this is called loss of heterozygosity (LOH). In this study we have analysed the DNA isolated from epitehlial cells from 164 cysts of 8 kidneys affected by ADPKD type I and 30 cysts form a kidney affected by ADPKD type II. We have demonstrated the presence of LOH in 20.1% of PKD1 cysts and in 10% of PKD2 cysts. We have also found eight other different mutations in PKD2 cysts without LOH; so the percentage of somatic mutations in the PKD2 kidney reaches 36.6% of cysts. In conclusion, our data suggest that a recessive mechanism at the cellular level is implicated in cyst formation in the PKD1 and the PKD2 disease. The loss of both copies of the gene triggers the proliferation of a single cell, resulting in the cyst formation.

[Mutational analysis of the PKD1 and PKD2 (type 1 and 2 dominant autosomal polycystic kidney) genes]. / Estudio mutacional de los genes PKD1 y PKD2 (poliquistosis renal autosómica dominante tipo 1 y 2).

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease. It is caused by mutations in at least two different genes: PKD1 and PKD2. The study of mutations in these genes is very difficult nowadays. In this study we have analyzed the non reiterated region of the PKD1 gene and all the exons and intron exon boundaries of the PKD2 gene. The technique used to study these genes have been single strand conformation analysis and heteroduplex. We have found 25 differences within the DNA sequence of the PKD1 gene with respect to the published sequence. Seven of these changes correspond to nonsense, missense, frameshifting and splicing mutations. The rest of changes correspond to polymorphisms or rare DNA variants. In the PKD2 gene we have identified 8 new mutations and one polymorphism. Six of these mutations are frameshifting, one is missense and the other one is a large deletion of the PKD2 gene. The rate of mutation detection within the PKD1 gene has been 4% and the rate for PKD2 has been 100%. We have not observed any correlation between genotype and phenotype either in the PKD1 nor in the PKD2 gene. The mutation analysis of ADPKD genes is very difficult, specially for the PKD1 gene. The rate of mutation detection is higher in the PKD2 gene but the global efficacy of the technique is very low as PKD2 represents only 15% of ADPKD patients. Nowadays linkage analysis is still the most useful technique for the molecular diagnosis of ADPKD patients.

The R453Q and D151A polymorphisms of hexose-6-phosphate dehydrogenase gene (H6PD) influence the polycystic ovary syndrome (PCOS) and obesity.

Hexose-6-phosphate dehydrogenase (H6PDH) influences 11ß-hydroxysteroid dehydrogenase activity, a key enzyme in the peripheral metabolism of cortisol that modulates insulin sensitivity in adipose tissue. To study the associations of R453Q and D151A polymorphisms in the H6PDH gene (H6PD) with polycystic ovary syndrome (PCOS) and their influence on clinical and metabolic variables, we genotyped 237 patients with PCOS and 135 control women for the R453Q (rs6688832) and D151A (rs34603401) variants in H6PD. The R453Q genotypes were distributed differently in patients and controls (χ(2)=9.55, P=0.002). Genotypes of D151A were distributed evenly in women with PCOS and controls, but showed a different distribution in non-obese and obese women (χ(2)=3.95, P=0.047), especially within the PCOS subgroup (χ(2)=4.65, P=0.031). A backward stepwise likelihood ratio logistic regression model (Nagelkerke's R(2)=0.490; χ(2)=164; P<0.0001) retained free testosterone (OR=1.13; 95% CI: 1.10-1.17) and H6PD Q453 alleles (OR=0.46; 95% CI: 0.27-0.79) as statistically significant predictors for PCOS, whereas homeostasis model assessment of insulin resistance and the H6PD D151A variant were excluded by the model. Both H6PD variants were associated with several phenotypic variables, including fasting insulin, homeostasis model assessment of insulin resistance and androstenedione levels. In summary, the R453Q and D151A variants of the H6PD gene are associated with PCOS and obesity, respectively, and may contribute to the PCOS phenotype by influencing obesity, insulin resistance and hyperandrogenism.

Adiponectin and resistin in PCOS: a clinical, biochemical and molecular genetic study.

BACKGROUND: We conducted a cross-sectional case-control study to evaluate the possible involvement of adiponectin and resistin in the pathogenesis of polycystic ovary syndrome (PCOS). METHODS: Seventy-six PCOS patients and 40 non-hyperandrogenic women matched for BMI and degree of obesity were included. Serum adiponectin and resistin levels, anthropometrical and hormonal variables, the 45 T-->G and 276 G-->T polymorphisms in the adiponectin gene, and the -420 C-->G variant in the resistin gene, were analysed. RESULTS: Serum adiponectin concentrations were reduced in PCOS patients compared with controls (P = 0.038) irrespective of the degree of obesity, whereas serum resistin levels were increased in overweight and obese women compared with lean subjects (P = 0.016), irrespective of their PCOS or controls status. The adiponectin and resistin polymorphisms were not associated with PCOS and did not influence serum levels of adiponectin, resistin and other clinical and hormonal variables. In a multiple regression model, the waist-to-hip ratio, free testosterone levels and age, but not insulin resistance, were the major determinants of hypoadiponectinaemia. CONCLUSIONS: PCOS patients present with hypoadiponectinaemia, in relation with abdominal adiposity and hyperandrogenism. Our present results suggest that hyperandrogenism and abdominal obesity, by reducing the serum levels of the insulin sensitizer adipokine adiponectin, might contribute to the insulin resistance of PCOS.

Evidence that colicin X is microcin B17.

The DNA replication inhibitor microcin B17 is a peptide antibiotic produced by Escherichia coli strains carrying plasmid pMccB17. Here we present evidence that antibiotic activities previously named colicin X are probably identical to microcin B17. Our results include comparison of the conditions of production of the antibiotics, their mode of action, cross-immunity of producer strains, and cross-resistance of resistant mutants. Plasmids encoding colicin X have been identified and shown to have a region of significant homology with the microcin B17-producing region of pMccB17 DNA.

appR gene product activates transcription of microcin C7 plasmid genes.

Microcin C7 (MccC7) is encoded by Escherichia coli plasmid pMccC7. However, some strains of E. coli K-12 carrying this plasmid do not produce this antibiotic. Here we show that these strains differ in the gene locus appR. This chromosomal gene product controls MccC7 production by activating the transcription of some, but not all, MccC7 plasmid genes.

Plasmid genes required for microcin B17 production.

The production of the antibiotic substance microcin B17 (Mcc) is determined by a 3.5-kilobase DNA fragment from plasmid pMccB17. Several Mcc- mutations on plasmid pMccB17 were obtained by both transposon insertion and nitrosoguanidine mutagenesis. Plasmids carrying these mutations were tested for their ability to complement Mcc- insertion or deletion mutations on pMM102 (pMM102 is a pBR322 derivative carrying the region encoding microcin B17). Results from these experiments indicate that at least four plasmid genes are required for microcin production.