The Caenorhabditis elegans sex determination gene mog-1 encodes a member of the DEAH-Box protein family.
In the Caenorhabditis elegans hermaphrodite germ line, the sex-determining gene fem-3 is repressed posttranscriptionally to arrest spermatogenesis and permit oogenesis. This repression requires a cis-acting regulatory element in the fem-3 3' untranslated region; the FBF protein, which binds to this element; and at least six mog genes. In this paper, we report the molecular characterization of mog-1 as well as additional phenotypic characterization of this gene. The mog-1 gene encodes a member of the DEAH-box family. Three mog-1 alleles possess premature stop codons and are likely to be null alleles, and one is a missense mutation and is likely to retain residual activity. mog-1 mRNA is expressed in both germ line and somatic tissues and appears to be ubiquitous. The MOG-1 DEAH-box protein is most closely related to proteins essential for splicing in the yeast Saccharomyces cerevisiae, but splicing appears to occur normally in a mog-1-null mutant. In addition to its involvement in the sperm-oocyte switch and control of fem-3, zygotic mog-1 is required for robust germ line proliferation and for normal growth during development. We suggest that mog-1 plays a broader role in RNA regulation than previously considered. (+info)
Linear SRY transcript in equine testis.
Employing a combination of reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) techniques, the complete coding sequence of cDNA for the equine SRY gene was determined. We also attempted to make clear whether the equine SRY gene transcript is expressed in the adult testis, and whether the type of transcript is expressed as linear or circular RNA. As a result, in total a 1420 bp cDNA sequence was determined. Accomplishment of 3' RACE infers that equine SRY gene was expressed as a linear RNA transcript in testicular tissue just after puberty, in contrast to the situation in mice. (+info)
Production of donor-derived offspring by transfer of primordial germ cells in Japanese quail.
We transfused concentrated primordial germ cells (PGCs) of the black strain (D: homozygous for the autosomal incomplete dominant gene, D) of quail into the embryos of the wild-type plumage strain (WP: d+/d+) of quail. The recipient quail were raised until sexual maturity and a progeny test of the putative germline chimeras was performed to examine the donor gamete-derived offspring (D/d+). Thirty-one percent (36/115) of the transfused quail hatched and 21 (13 females and 8 males) of them reached maturity. Five females and 2 males were germline chimeras producing donor gamete-derived offspring. Transmission rates of the donor derived gametes in the chimeric females and males were 1.8-8.3% and 2.6-63.0%, respectively. Germline chimeric and the other putative chimeric males were also test-mated with females from the sex-linked imperfect albino strain (AL: d+/d+, al/W, where al indicates the sex-linked imperfect albino gene on the Z chromosome, and W indicates the W chromosome) for autosexing of W-bearing spermatozoa: No albino offspring were born. (+info)
Temperature-dependent sex determination: upregulation of SOX9 expression after commitment to male development.
In mammals, birds and reptiles the morphological development of the gonads appear to be conserved. This conservation is evident despite the different sex determining switches employed by these vertebrate groups. Mammals exhibit chromosomal sex determination (CSD) where the key sex determining switch is the Y-linked gene, SRY. Although SRY is the trigger for testis determination in mammals, it is not conserved in other vertebrate groups. However, a gene closely related to SRY, the highly conserved transcription factor, SOX9, plays an important role in the testis pathway of mammals and birds. In contrast to the CSD mechanism evident in mammals and birds, many reptiles exhibit temperature dependent sex determination (TSD) where the egg incubation temperature triggers sex determination. Here we examine the expression of SOX9 during gonadogenesis in the American alligator, (Alligator mississippiensis), a reptile that exhibits TSD. Alligator SOX9 is expressed in the embryonic testis but not in the ovary. However, the timing of SOX9 upregulation in the developing testis is not consistent with a role for this gene in the early stages of alligator sex determination. Since SOX9 upregulation in male embryos coincides with the structural organisation of the testis, SOX9 may operate farther downstream in the vertebrate sex differentiation pathway than previously postulated. (+info)
Evidence for multiple promoter elements orchestrating male-specific regulation of the her-1 gene in Caenorhabditis elegans.
The sex-determining gene her-1 is required for male development in Caenorhabditis elegans. In XO males, two her-1 mRNAs, her-1a and her-1b, are transcribed from two separate promoters: P1, located in the 5'-flanking region, and P2, located in the large second intron. In XX hermaphrodites, accumulation of both her-1 transcripts is repressed by the sdc genes, which in turn are negatively regulated by the xol-1 gene. When introduced into a xol-1(y9) background, transgenic arrays, including 3.4 kb of her-1 intron 2 sequence (P2), result in phenotypes that mimic those of sdc(lf) mutants, including suppression of XO lethality and masculinization of both XX and XO animals. The masculinization, but not the suppression of XO lethality, is dependent on endogenous her-1 activity. These effects could therefore result from sequestration (titration) of sdc gene products by sequences in the arrays, causing derepression of her-1 (masculinizing effect) and disruption of the dosage compensation machinery (allowing survival of XO animals). We used these effects as an assay in a deletion analysis of the two her-1 promoter regions to define potential cis-regulatory sites required for the putative titration. Several regions in P2 contributed to these effects. P1 was effective only in combination with certain P2 sequences and only if a particular P1 site previously implicated in her-1 repression was intact. These results suggest that normal repression of transcription from P1 in XX animals may involve cooperative interaction with sequences in the P2 region. In experiments to test for a possible role of the her-1b transcript in regulation of sdc genes, no significant effects could be demonstrated. (+info)
Preimplantation genetic diagnosis using fluorescent polymerase chain reaction: results and future developments.
PURPOSE: Fluorescent polymerase chain reaction (PCR) is a multipurpose technique that can be used for diagnosing sex, single-gene defects, and trisomies as well as determining DNA fingerprints from single cells. However, its effectiveness must be assessed before clinical preimplantation genetic diagnosis (PGD) application. METHODS: Single and multiplex fluorescent PCR was applied to single cells and blastomeres. RESULTS: Fluorescent PCR can be used to diagnose sex from blastomeres and has been successfully applied in a clinical PGD sexing program resulting in a confirmed pregnancy. A further major advantage of fluorescent PCR is the ability to multiplex, providing multiple diagnoses and DNA fingerprints with a high reliability (approximately 75% for trisomy, 86% for DNA fingerprint) and good accuracy (70-80%). Allele dropout in multiplex PCR is approximately 20% per allele and does not appear to be associated with the fragment size. CONCLUSIONS: Fluorescent PCR is a powerful technique for PGD, and the effects of allele dropout must be considered, particularly in multiplex PCR. (+info)
Sexual behaviour: Courting dissatisfaction.
A nuclear receptor, the product of the dissatisfaction gene, has been found to regulate Drosophila sexual behaviour, probably via its action in a small subset of neurons. The results shed new light on the genetic determination of sexual behaviour. (+info)
Retroactive DNA analysis for sex determination and dystrophin gene by polymerase chain reaction with archived cytogenetic slides.
We describe a rapid and efficient diagnostic method for sex determination and the dystrophin gene by the polymerase chain reaction (PCR) using archived cytogenetic slides. Archived cytogenetic slides stored for about 4 years at room temperature were used. To confirm whether DNA analysis is possible using the archived cytogenetic slides, we extracted the DNA from the slides and amplified the Y centromeric region (DYZ3), the X centromeric region (DXZ1) and the exon 46 of the dystrophin gene. Of the 50 cases, 24 were peripheral bloods, 13 were amniotic fluid cells, 5 were chorionic villus samplings and 8 were cord bloods. The PCR related sex determination in 22 females and 28 males, showed 100% concordance with the results of chromosome analysis, and all cases showed positive band for the exon 46 of the dystrophin gene. Of the 50 cases of the archived cytogenetic slides, we were fortunate enough to obtain the fresh blood sample from one fetus whose karyotype showed 45,X/46,X,+mar to compare the results of the gDNA with that from archived cytogenetic slide. To confirm whether the marker chromosome was derived from Y chromosome, we studied the six loci (PABY, SRY, RPS4Y (SY16, 17), ZFY, DYS14) on the short arm, one locus (DYZ3) on the centromere and one locus (DYZ1) on the long arm. Of the 8 loci studies, all PCR related Y chromosome showed positive band from both gDNA obtained from cord blood and archived cytogenetic slides. We could conclude from the above results that the marker chromosome was derived from the Y chromosome. We believe our experiment is rapid and efficient for studies of over 10 independent loci from a single slide which has been kept in storage for up to 4 years and that archival Giemsa-stained cytogenetic slide repositories represent valuable DNA resources for clinical and forensic studies. (+info)