scholarly journals The Drosophila melanogaster Sex Determination Gene sisA Is Required in Yolk Nuclei for Midgut Formation

Genetics ◽  
2000 ◽  
Vol 155 (1) ◽  
pp. 191-202 ◽  
Author(s):  
Jeffrey J Walker ◽  
Karin K Lee ◽  
Rushin N Desai ◽  
James W Erickson
Keyword(s):  
Sex Determination ◽  
Null Allele ◽  
Gut Development ◽  
Direct Role ◽  
Yolk Cell ◽  
Gene Functions ◽  
Essential Function ◽  
Sex Lethal ◽  
Key Aspects

Abstract During sex determination, the sisterlessA (sisA) gene functions as one of four X:A numerator elements that set the alternative male or female regulatory states of the switch gene Sex-lethal. In somatic cells, sisA functions specifically in sex determination, but its expression pattern also hints at a role in the yolk cell, a syncytial structure believed to provide energy and nutrients to the developing embryo. Previous studies of sisA have been limited by the lack of a null allele, leaving open the possibility that sisA has additional functions. Here we report the isolation and molecular characterization of four new sisA alleles including two null mutations. Our findings highlight key aspects of sisA structure-function and reveal important qualitative differences between the effects of sisA and the other strong X:A numerator element, sisterlessB, on Sex-lethal expression. We use genetic, expression, clonal, and phenotypic analyses to demonstrate that sisA has an essential function in the yolk nuclei of both sexes. In the absence of sisA, endoderm migration and midgut formation are blocked, suggesting that the yolk cell may have a direct role in larval gut development. To our knowledge, this is the first report of a requirement for the yolk nuclei in Drosophila development.

scholarly journals The Drosophila sex determination gene snf is utilized for the establishment of the female-specific splicing pattern of Sex-lethal.

Genetics ◽  
1993 ◽  
Vol 134 (3) ◽  
pp. 801-807
Author(s):  
E B Albrecht ◽  
H K Salz
Keyword(s):  
Sex Determination ◽  
Rna Splicing ◽  
Null Allele ◽  
Early Embryogenesis ◽  
Wild Type ◽  
Female Progeny ◽  
Splicing Pattern ◽  
Late Embryogenesis ◽  
Sex Lethal ◽  
Female Specific

Abstract The Drosophila snf gene is a positive regulator of the sex determination gene Sex-lethal in both the germline and the soma. Its role in the soma is only evident when the probability of Sex-lethal activation has been reduced. For instance, in an otherwise wild-type background, females homozygous for a weak snf mutation produce both male and female progeny; however, when mated to males hemizygous for a null allele of Sex-lethal, they produce only male progeny. We demonstrate that the lack of female progeny is due to aberrant Sex-lethal regulation in late embryogenesis. In these mutant embryos, there is little accumulation of the late female-specific spliced RNAs and proteins. In contrast, in early embryogenesis, Sex-lethal regulation is not affected. The accumulation of both the early Sex-lethal transcripts and proteins is normal. These results suggest that the wild-type product of snf plays an important role in establishing the female-specific RNA splicing pattern of Sex-lethal. Whether snf influences the female-specific splice site choice directly or indirectly remains to be determined.

scholarly journals Molecular characterization of the her-1 gene suggests a direct role in cell signaling during Caenorhabditis elegans sex determination.

1993 ◽  
Vol 7 (2) ◽  
pp. 216-228 ◽  
Author(s):  
M D Perry ◽  
W Li ◽  
C Trent ◽  
B Robertson ◽  
A Fire ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Cell Signaling ◽  
Sex Determination ◽  
Molecular Characterization ◽  
Direct Role

scholarly journals Sex-specific control of Sex-lethal is a conserved mechanism for sex determination in the genus Drosophila

Development ◽  
1996 ◽  
Vol 122 (3) ◽  
pp. 971-982 ◽  
Author(s):  
D. Bopp ◽  
G. Calhoun ◽  
J.I. Horabin ◽  
M. Samuels ◽  
P. Schedl
Keyword(s):  
Sex Determination ◽  
Polytene Chromosomes ◽  
Specific Pattern ◽  
Specific Expression ◽  
Sequence Organization ◽  
Amino Terminal ◽  
Splicing Pattern ◽  
Sex Lethal ◽  
Specific Control

In D. melanogaster the binary switch gene Sex-lethal (Sxl) plays a pivotal role in somatic sex determination -- when the Sxl gene is on the female pathway is followed, while the male pathway is followed when the gene is off. In the present study we have asked whether the Sxl gene is present in other species of the genus Drosophila and whether it is subject to a similar sex-specific on-off regulation. Sxl proteins were found in all of the drosophilids examined, and they display a sex-specific pattern of expression. Furthermore, characterization of the Sxl gene in the distant drosophilan relative, D. virilis, reveals that the structure and sequence organization of the gene has been well conserved and that, like melanogaster, alternative RNA processing is responsible for its sex-specific expression. Hence, this posttranscriptional on-off regulatory mechanism probably existed before the separation of the drosophilan and sophophoran subgenera and it seems likely that Sxl functions as a sex determination switch gene in most species in the Drosophila genus. Although alternative splicing appears to be responsible for the on-off regulation of the Sxl gene in D. virilis, this species is unusual in that Sxl proteins are present not only in females but also in males. The D. virilis female and male proteins appear to be identical over most of the length except for the amino-terminal approx. 25 aa which are encoded by the differentially spliced exons. In transcriptionally active polytene chromosomes, the male and female proteins bind to the same cytogenetic loci, including the sites corresponding to the D. virilis Sxl and tra genes. Hence, though the male proteins are able to interact with appropriate target pre-mRNAs, they are apparently incapable of altering the splicing pattern of these pre-mRNAs.

scholarly journals Ultrafiltration Method for Plasma Protein Binding Studies and Its Limitations

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 382
Author(s):  
Camelia-Maria Toma ◽  
Silvia Imre ◽  
Camil-Eugen Vari ◽  
Daniela-Lucia Muntean ◽  
Amelia Tero-Vescan
Keyword(s):  
Protein Binding ◽  
Plasma Protein Binding ◽  
Plasma Protein ◽  
Specific Binding ◽  
Critical Role ◽  
Volume Ratio ◽  
Binding Studies ◽  
Experimental Conditions ◽  
Key Aspects

Plasma protein binding plays a critical role in drug therapy, being a key part in the characterization of any compound. Among other methods, this process is largely studied by ultrafiltration based on its advantages. However, the method also has some limitations that could negatively influence the experimental results. The aim of this study was to underline key aspects regarding the limitations of the ultrafiltration method, and the potential ways to overcome them. The main limitations are given by the non-specific binding of the substances, the effect of the volume ratio obtained, and the need of a rigorous control of the experimental conditions, especially pH and temperature. This review presents a variety of methods that can hypothetically reduce the limitations, and concludes that ultrafiltration remains a reliable method for the study of protein binding. However, the methodology of the study should be carefully chosen.

scholarly journals Copy Number Variation and Rearrangements Assessment in Cancer: Comparison of Droplet Digital PCR with the Current Approaches

2021 ◽  
Vol 22 (9) ◽  
pp. 4732
Author(s):  
Vincenza Ylenia Cusenza ◽  
Alessandra Bisagni ◽  
Monia Rinaldini ◽  
Chiara Cattani ◽  
Raffaele Frazzi
Keyword(s):  
Digital Pcr ◽  
Genetic Alterations ◽  
Droplet Digital Pcr ◽  
Molecular Oncology ◽  
Therapeutic Choice ◽  
Golden Standard ◽  
Number Variation ◽  
Key Aspects

The cytogenetic and molecular assessment of deletions, amplifications and rearrangements are key aspects in the diagnosis and therapy of cancer. Not only the initial evaluation and classification of the disease, but also the follow-up of the tumor rely on these laboratory approaches. The therapeutic choice can be guided by the results of the laboratory testing. Genetic deletions and/or amplifications directly affect the susceptibility or the resistance to specific therapies. In an era of personalized medicine, the correct and reliable molecular characterization of the disease, also during the therapeutic path, acquires a pivotal role. Molecular assays like multiplex ligation-dependent probe amplification and droplet digital PCR represent exceptional tools for a sensitive and reliable detection of genetic alterations and deserve a role in molecular oncology. In this manuscript we provide a technical comparison of these two approaches with the golden standard represented by fluorescence in situ hybridization. We also describe some relevant targets currently evaluated with these techniques in solid and hematologic tumors.

scholarly journals Genetic and Molecular Characterization of sting, a Gene Involved in Crystal Formation and Meiotic Drive in the Male Germ Line of Drosophila melanogaster

Genetics ◽  
1999 ◽  
Vol 151 (2) ◽  
pp. 749-760 ◽  
Author(s):  
Armin Schmidt ◽  
Gioacchino Palumbo ◽  
Maria P Bozzetti ◽  
Patrizia Tritto ◽  
Sergio Pimpinelli ◽  
...  
Keyword(s):  
Amino Acids ◽  
Drosophila Melanogaster ◽  
Null Allele ◽  
Germ Line ◽  
Meiotic Drive ◽  
P Element ◽  
Crystal Formation ◽  
Male Sterile ◽  
Male Sterile Mutation

Abstract The sting mutation, caused by a P element inserted into polytene region 32D, was isolated by a screen for male sterile insertions in Drosophila melanogaster. This sterility is correlated with the presence of crystals in spermatocytes and spermatids that are structurally indistinguishable from those produced in males carrying a deficiency of the Y-linked crystal (cry) locus. In addition, their morphology is needle-like in Ste+ flies and star-shaped in Ste flies, once again as observed in cry– males. The sti mutation leads to meiotic drive of the sex chromosomes, and the strength of the phenomenon is correlated with the copy number of the repetitive Ste locus. The same correlation is also true for the penetrance of the male sterile mutation. A presumptive sti null allele results in male sterility and lethal maternal effect. The gene was cloned and shown to code for a putative protein that is 866 amino acids long. A C-terminal domain of 82 amino acids is identified that is well conserved in proteins from different organisms. The gene is expressed only in the germline of both sexes. The interaction of sting with the Ste locus can also be demonstrated at the molecular level. While an unprocessed 8-kb Ste primary transcript is expressed in wild-type males, in X/Y homozygous sti males, as in X/Y cry– males, a 0.7-kb mRNA is produced.

Characterization of ethylene effects on sex determination in cucumber plants

2003 ◽  
Vol 16 (3) ◽  
pp. 103-111 ◽  
Author(s):  
Seiji Yamasaki ◽  
Nobuharu Fujii ◽  
Hideyuki Takahashi
Keyword(s):  
Sex Determination

Induction of female Sex-lethal RNA splicing in male germ cells: implications for Drosophila germline sex determination

Development ◽  
1997 ◽  
Vol 124 (24) ◽  
pp. 5033-5048 ◽  
Author(s):  
J.H. Hager ◽  
T.W. Cline
Keyword(s):  
Sex Determination ◽  
Germ Cells ◽  
Rna Splicing ◽  
Feedback Loop ◽  
Dose Effect ◽  
Male Germ Cells ◽  
Control Female ◽  
Sex Lethal ◽  
Specific Regulation ◽  
Female Specific

With a focus on Sex-lethal (Sxl), the master regulator of Drosophila somatic sex determination, we compare the sex determination mechanism that operates in the germline with that in the soma. In both cell types, Sxl is functional in females (2X2A) and nonfunctional in males (1X2A). Somatic cell sex is determined initially by a dose effect of X:A numerator genes on Sxl transcription. Once initiated, the active state of SXL is maintained by a positive autoregulatory feedback loop in which Sxl protein insures its continued synthesis by binding to Sxl pre-mRNA and thereby imposing the productive (female) splicing mode. The gene splicing-necessary factor (snf), which encodes a component of U1 and U2 snRNPs, participates in this RNA splicing control. Here we show that an increase in the dose of snf+ can trigger the female Sxl RNA splicing mode in male germ cells and can feminize triploid intersex (2X3A) germ cells. These snf+ dose effects are as dramatic as those of X:A numerator genes on Sxl in the soma and qualify snf as a numerator element of the X:A signal for Sxl in the germline. We also show that female-specific regulation of Sxl in the germline involves a positive autoregulatory feedback loop on RNA splicing, as it does in the soma. Neither a phenotypically female gonadal soma nor a female dose of X chromosomes in the germline is essential for the operation of this feedback loop, although a female X-chromosome dose in the germline may facilitate it. Engagement of the Sxl splicing feedback loop in somatic cells invariably imposes female development. In contrast, engagement of the Sxl feedback loop in male germ cells does not invariably disrupt spermatogenesis; nevertheless, it is premature to conclude that Sxl is not a switch gene in germ cells for at least some sex-specific aspects of their differentiation. Ironically, the testis may be an excellent organ in which to study the interactions among regulatory genes such as Sxl, snf, ovo and otu which control female-specific processes in the ovary.

scholarly journals The Transcriptional Regulator Hap1p (Cyp1p) Is Essential for Anaerobic or Heme-Deficient Growth of Saccharomyces cerevisiae: Genetic and Molecular Characterization of an Extragenic Suppressor that Encodes a WD Repeat Protein

Genetics ◽  
1998 ◽  
Vol 148 (2) ◽  
pp. 559-569 ◽  
Author(s):  
Yann Chantrel ◽  
Mauricette Gaisne ◽  
Claire Lions ◽  
Jacqueline Verdière
Keyword(s):  
Profile Analysis ◽  
Signal Transduction Pathway ◽  
Cysteine Residue ◽  
Sequence Comparisons ◽  
Dependent Signal ◽  
Polysome Profile ◽  
Essential Function ◽  
Wd Repeat ◽  
Extragenic Suppressors

Abstract We report here that Hap1p (originally named Cyp1p) has an essential function in anaerobic or heme-deficient growth. Analysis of intragenic revertants shows that this function depends on the amino acid preceding the first cysteine residue of the DNA-binding domain of Hap1p. Selection of recessive extragenic suppressors of a hap1−hem1− strain allowed the identification, cloning, and molecular analysis of ASC1 (Cyp1 Absence of growth Supressor). The sequence of ASC1 reveals that its ORF is interrupted by an intron that shelters the U24 snoRNA. Deletion of the intron, inactivation of the ORF, and molecular localization of the mutations show unambiguously that it is the protein and not the snoRNA that is involved in the suppressor phenotype. ASC1, which is constitutively transcribed, encodes an abundant, cytoplasmically localized 35-kD protein that belongs to the WD repeat family, which is found in a large variety of eucaryotic organisms. Polysome profile analysis supports the involvement of this protein in translation. We propose that the absence of functional Asc1p allows the growth of hap1−hem1− cells by reducing the efficiency of translation. Based on sequence comparisons, we discuss the possibility that the protein intervenes in a kinase-dependent signal transduction pathway involved in this last function.

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