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P Berta

Publications and source records attributed to P Berta.

At least 55 records · Page 3Linked to original sources
PubMed1994

Description and functional implications of a novel mutation in the sex-determining gene SRY.

The sex-determining gene SRY was screened for molecular alteration in an XY sex-reversed female by single-strand conformation polymorphism (SSCP) technique. An A-to-G transition was detected which leads to an exchange of a tyrosine by a cysteine in the SRY protein. The affected tyrosine residue located at the C terminus of the DNA binding protein is evolutionarily strongly conserved among the members of the HMG box containing proteins. Using gel shift assay and peptide synthesis such a mutation is shown to abolish the SRY protein DNA binding ability. The involvement of this particular amino acid in the binding specificity is also discussed.

Adolescent↗
PubMed1994

The human testis determining factor SRY: a new member of the HMG box protein family.

The product of the sex-determining gene SRY is a member of the HMG box containing protein superfamily. The HMG box is a DNA-binding domain of about 80 amino acids shared by many proteins with diverse functions. It seems that the functions of the full length protein are restricted to the HMG box but their molecular basis remains to be determined. We have summarized here the properties of this binding domain described so far in the literature and, using a synthetic peptide mimicking the DNA binding domain (SRY80), we have confirmed the existence of DNA minor groove contacts with this domain. Using intrinsic fluorescence of the tryptophane, the interaction between SRY80 and the putative target sequence AACAAAT was also quantified. In conclusion, we also consider the possible putative action of SRY to fulfill its role in sex determination.

Amino Acid Sequence↗
PubMed1994

[Human testicular determining factor: from the gene to protein].

Since its cloning in 1990, the human SRY gene has been formally identified with the testis determining factor. The SRY gene encodes a 204 amino acid protein of the High Mobility Group family. Its ability to bind DNA, to bend DNA or to be translocated into the nuclear compartment of the cell have now been established. However, neither its mode of action nor the description of target genes have been described so far, and are the topics of many studies.

Amino Acid Sequence↗
PubMed1994

[Genes of the Y chromosome and Turner syndrome].

Turner syndrome is a complex human phenotype most commonly seen in association with a 45,X karyotype and it has been proposed that the phenotype is the result of monosomy for genes common to the X and Y chromosomes. Detection of unrecognized Y derived material is now possible by PCR of the SRY gene. Its presence is correlated with the presence of testicular tissue, known to increase the risk of developing gonadal neoplasia. Study of Y chromosome allowed the localisation of a candidate gene for the development of gonadoblastoma, GBY. Moreover, some groups described genes on the Y chromosome whose defects seem to be involved in the development of Turner stigmata: ZFY and RPS4Y. In conclusion; molecular genetics of the Y chromosome develops new pathophysiological and fundamental perspectives of the molecular genetics of the Turner syndrome.

Chromosome Mapping↗
PubMed1993

Distinct molecular origins for Denys-Drash and Frasier syndromes.

The direct involvement of the Wilm's tumor suppressor gene (WT1) in Denys-Drash syndrome through mutations within exons 8 or 9 has recently been established. The absence of such alterations in three patients with Frasier syndrome provides a molecular basis for distinguishing these two syndromes that are associated with streak gonads, pseudohermaphroditism and renal failure.

Base Sequence↗
PubMed1993

Anti-müllerian hormone in early human development.

Anti-müllerian hormone (AMH) is a glycoprotein produced by immature Sertoli cells and responsible for the regression of müllerian ducts in male fetuses. The ontogeny of the hormone in early human development was investigated. While no detectable AMH could be found in female fetal serum, in males, the mean +/- S.E.M. AMH serum concentration was 40.5 +/- 3.9 ng/ml from 19 to 30 weeks (n = 13), and 28.4 +/- 6.1 ng/ml from 30 weeks to term (n = 9). The latter value is significantly different from the mean AMH concentration in serum from boys aged 2 months to 2 years (43.1 +/- 3.7), suggesting that AMH production is sluggish during the perinatal period. The serum AMH concentration of a 46,XX male fetus was in the normal range for males. Using in situ hybridization, AMH transcripts were detected in the testicular tissue of all fetuses from 8 weeks onwards, but not in fetal ovaries nor in the yet undifferentiated gonadal tissue of a 7-week-old fetus bearing male-determining DNA sequences. Together, these data indicate that AMH is a reliable marker for the presence of functional testicular tissue and, as such, may be helpful for the diagnosis of fetal sex, particularly in the presence of sex chromosome abnormalities.

Amniotic Fluid↗
PubMed1993

Complete androgen insensitivity syndrome associated with a de novo mutation of the androgen receptor gene detected by single strand conformation polymorphism.

In a French child with complete androgen insensitivity syndrome and negative receptor-binding, no gross deletion has been found. Using single-strand conformation polymorphism assay, a useful screening method for rapid detection of DNA sequence alterations, and direct DNA sequencing, a G-T nucleotide substitution in exon 5 of the androgen receptor gene at nucleotide 2590 was found. This changed codon 743, glycine to valine, in the hormone-binding domain and created a new recognition sequence for the restriction endonuclease Asp HI. Amplification of exon 5 by polymerase chain reaction followed by digestion with Asp HI enabled easy recognition of the described mutation. Since the mother's exon 5 was undigested, we suspected the de novo nature of this nucleotide substitution. This was confirmed by direct sequencing of the mother's DNA which only showed the canonical sequence. To our knowledge, there has been no previous report of a de novo mutation described within the androgen receptor gene in patients with androgen insensitivity syndrome.

Amino Acid Sequence↗
PubMed1993

PCR analysis and sequencing of the SRY sex determining gene in four patients with bilateral congenital anorchia.

OBJECTIVE: We explored the possibility of a genetic anomaly in the sex determining region of the Y chromosome, SRY gene, known to be equated to the testis determining region. PATIENTS: Four patients with bilateral congenital anorchia, absence of testicular tissue, elevated FSH and a lack of testosterone response to human chorionic gonadotrophin stimulation tests were studied. MEASUREMENTS: Amplification by polymerase chain reaction of the SRY gene and direct double stranded DNA sequencing were performed with the same primers. RESULTS: The expected 648 basepairs band of SRY was detected in the four DNA samples from patients with bilateral congenital anorchia. Direct sequencing did not show any difference with the previous published sequence. CONCLUSIONS: These data suggest that, in the four patients, bilateral congenital anorchia is not related to an anomaly of the opening reading frame sequence of the SRY gene.

Child, Preschool↗
PubMed1992

Synthesis of a large peptide mimicking the DNA binding properties of the sex determining protein, SRY.

The sex determining protein, SRY, has been recently described as containing a DNA binding motif, also called the SRY box. This 80 amino acid box was synthesized using the continuous flow solid-phase technique. The product was then purified and tested according to such diverse criteria as its intrinsic structure or its biological activity (DNA binding capacity), and compared to the full-length protein. The data indicate that the peptide is relevant for the properties described so far for the protein.

Amino Acid Sequence↗
PubMed1992

Mutational analysis of SRY: nonsense and missense mutations in XY sex reversal.

XY females (n = 17) were analysed for mutations in SRY (sex-determining region Y gene), a gene that has recently been equated with the testis determining factor (TDF). SRY sequences were amplified by the polymerase chain reaction (PCR) and analysed by both the single strand conformational polymorphism assay (SSCP) and DNA sequencing. The DNA from two individuals gave altered SSCP patterns; only these two individuals showed any DNA sequence variation. In both cases, a single base change was found, one altering a tryptophan codon to a stop codon, the other causing a glycine to arginine amino acid substitution. These substitutions lie in the high mobility group (HMG)-related box of the SRY protein, a potential DNA-binding domain. The corresponding regions of DNA from the father of one individual and the paternal uncle of the other, were sequenced and found to be normal. Thus, in both cases, sex reversal is associated with de novo mutations in SRY. Combining this data with two previously published reports, a total of 40 XY females have now been analysed for mutations in SRY. The number of de novo mutations in SRY is now doubled to four, adding further strength to the argument that SRY is TDF.

Base Sequence↗
PubMed1992

Molecular analysis of the sex-determining region from the Y chromosome in two patients with Frasier syndrome.

In the Frasier syndrome there is an association between XY gonadal dysgenesis and chronic renal failure. Owing to an observed sex reversal, the Y chromosomes of two girls with this syndrome have been analyzed. Using molecular-biology techniques, no major alterations of the known sex-determining area of the Y chromosome were found. Furthermore, the sequence did not reveal impairment of the recently described testis-determining factor SRY. These data suggest that in the Frasier syndrome, XY sex reversal and renal failure could be the result of either faulty gene(s) located downstream in the sex differentiation pathway during embryogenesis, or impaired SRY regulation. Preliminary results on the Wilms' tumor suppressor gene WT1, a candidate for acting downstream to SRY, are also provided.

Adolescent↗
PubMed1992

Screening for Y-derived sex determining gene SRY in 40 patients with Turner syndrome.

In Turner patients, the presence of a Y chromosome or derivative Y is correlated with the risk of gonadoblastoma induction. "Marker" chromosomes originating from Y, may not show characteristic fluorescence and then be very difficult to identify by conventional cytogenetic techniques, although they still predispose the patients to gonadal tumors. Using polymerase chain reaction of the gene from the sex-determining region of the Y chromosome, we screened 40 Turner patients (thirty seven 45X and three 45X,46XX) for the presence of Y chromosomal DNA. We were able to identify karyotypically unrecognized Y chromosome material in 1 patient out of the 40 studied. In this patient mild clinical and biological hyperandrogenism was observed. Reliability of our technique was ascertained by the detection of the expected 648 base pairs amplified DNA fragment in all normal male controls as well as in 3 Turner patients with confirmed 45X,46XY mosaicism. Despite the low frequency of unrecognized Y chromosome material (1 case over 40 in our experience), our data suggest that polymerase chain reaction of the gene from the sex-determining region of the Y chromosome is worthy of being performed in Turner patients considering the potential risk of the presence of a Y chromosome.

Adolescent↗
PubMed1991

Testis-determining factor and Y-linked sex reversal.

A gene named SRY, isolated last year from the sex-determining region of the human Y chromosome, satisfies many of the criteria expected of the testis-determining factor gene. Mutations in SRY have been found in XY females, strongly implicating SRY as the testis-determining gene.

Animals↗
PubMed1991

Responses of subcultured rat aortic smooth muscle myocytes to vasoactive agents and KCl-induced depolarization.

We have developed a culture system in which a single-mass primary culture can be used for as long as 6 wk as a source of subcultured smooth muscle myocytes for the study of the changes of their shape upon addition of vasoactive agents (angiotensin, vasopressin, norepinephrine, and serotonin) and KCl depolarization. Responses of subcultivated myocytes were shown to be reproducible with time in primary culture before subculture and consistent with responses of thoracic aorta to the same agents. Effect of KCl depolarization could be blocked with calcium antagonist PN 200-110. Consistently, the presence of calcium L-channels was shown using whole cell patch-clamp recordings. A comparative study of the responses of myocytes derived from two different segments of the thoracic aorta showed that these cells displayed responses with different maximal amplitudes and the same potencies according to their topological origin in the vessel.

Angiotensin II↗
PubMed1991

[Determination of sex and Y chromosome].

Years of speculations about the nature of the elusive testis determining factor (TDF) of the Y chromosome have ended last year. A gene named SRY satisfies many criteria expected of the testis determining gene, and gives us a basis to understand molecular mechanisms of the testis differentiation. The different steps which gave rise to SRY cloning are described.

DNA-Binding Proteins↗