Molecular genetic aspects of sex determination in Drosophila melanogaster

Genome ◽  
1989 ◽  
Vol 31 (2) ◽  
pp. 638-645 ◽  
Author(s):  
B. S. Baker ◽  
K. Burtis ◽  
T. Goralski ◽  
W. Mattox ◽  
R. Nagoshi
Keyword(s):  
Drosophila Melanogaster ◽  
Sex Determination ◽  
Sexual Differentiation ◽  
Rna Processing ◽  
Molecular Basis ◽  
Rna Binding ◽  
Regulatory Genes ◽  
Regulatory State ◽  
Splice Acceptor ◽  
Regulatory Cascade

The molecular analyses of three of the regulatory genes (transformer (tra), doublesex (dsx), and transformer-2 (tra-2)) controlling sexual differentiation in Drosophila have demonstrated that the control of RNA processing has a major role in regulating somatic sexual differentiation. The activities of both the tra and dsx genes are controlled at the level of RNA processing. In the case of tra the use of different splice acceptor sites results in a functional transcript being produced only in females, whereas at dsx the use of different splice acceptor sites in the two sexes results in the production of transcripts that encode different proteins in males and females. The tra-2 gene has been shown to be necessary for the processing of the dsx pre-mRNA in females and the conceptual translation of a tra-2 cDNA shows that it encodes a protein with similarity to a family of RNA-binding proteins which includes known splicesome components. We previously suggested that the pattern of sexual differentiation and dosage compensation characteristic of a male was a default regulatory state. The findings reviewed here provide a molecular basis for this default expression in males as well as an insight into how females differ from males in control of the expression of these genes. For both the tra and dsx genes the molecular basis of their male (default) state of expression appears to be the processing of their transcripts by the housekeeping RNA splicing machinery. In females the specification of the alternative pattern of splicing at both tra and dsx is by the sex determination regulatory genes that function upstream of them in this regulatory cascade. It seems likely that the activities of these sex determination regulatory genes in females do not provide all of the information that is necessary for proper splicing of the transcripts of the genes downstream of them. Rather we imagine that the products of the Sxl, tra, and tra-2 genes are acting to impose a specificity on the basic cellular splicing machinery.Key words: Drosophila melanogaster, sex determination, sexual differentiation.

scholarly journals A genetic analysis of hermaphrodite, a pleiotropic sex determination gene in Drosophila melanogaster.

Genetics ◽  
1994 ◽  
Vol 136 (1) ◽  
pp. 195-207
Author(s):  
M A Pultz ◽  
G S Carson ◽  
B S Baker
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Analysis ◽  
Sex Determination ◽  
Temperature Sensitivity ◽  
Sexual Differentiation ◽  
Regulatory Genes ◽  
Temperature Sensitive ◽  
Partial Loss ◽  
Female Progeny ◽  
Regulatory Cascade

Abstract Sex determination in Drosophila is controlled by a cascade of regulatory genes. Here we describe hermaphrodite (her), a new component of this regulatory cascade with pleiotropic zygotic and maternal functions. Zygotically, her+ function is required for female sexual differentiation: when zygotic her+ function is lacking, females are transformed to intersexes. Zygotic her+ function may also play a role in male sexual differentiation. Maternally, her+ function is needed to ensure the viability of female progeny: a partial loss of her+ function preferentially kills daughters. In addition, her has both zygotic and maternal functions required for viability in both sexes. Temperature sensitivity prevails for all known her alleles and for all of the her phenotypes described above, suggesting that her may participate in an intrinsically temperature-sensitive process. This analysis of four her alleles also indicates that the zygotic and maternal components of of her function are differentially mutable. We have localized her cytologically to 36A3-36A11.

Regulation of Sexual Dimorphism in Mammals

1998 ◽  
Vol 78 (1) ◽  
pp. 1-33 ◽  
Author(s):  
CHRISTOPHER M. HAQQ ◽  
PATRICIA K. DONAHOE
Keyword(s):  
Sexual Dimorphism ◽  
Sex Determination ◽  
Cell Fate ◽  
Middle Ages ◽  
Sexual Differentiation ◽  
Molecular Basis ◽  
Sex Differentiation ◽  
Specific Gene ◽  
Single Individual ◽  
Cell Fate Decisions

Haqq, Christopher M., and Patricia K. Donahoe. Regulation of Sexual Dimorphism in Mammals. Physiol. Rev. 78: 1–33, 1998. — Sexual dimorphism in humans has been the subject of wonder for centuries. In 355 BC, Aristotle postulated that sexual dimorphism arose from differences in the heat of semen at the time of copulation. In his scheme, hot semen generated males, whereas cold semen made females (Jacquart, D., and C. Thomasset. Sexuality and Medicine in the Middle Ages, 1988). In medieval times, there was great controversy about the existence of a female pope, who may have in fact had an intersex phenotype (New, M. I., and E. S. Kitzinger. J. Clin. Endocrinol. Metab. 76: 3–13, 1993.). Recent years have seen a resurgence of interest in mechanisms controlling sexual differentiation in mammals. Sex differentiation relies on establishment of chromosomal sex at fertilization, followed by the differentiation of gonads, and ultimately the establishment of phenotypic sex in its final form at puberty. Each event in sex determination depends on the preceding event, and normally, chromosomal, gonadal, and somatic sex all agree. There are, however, instances where chromosomal, gonadal, or somatic sex do not agree, and sexual differentiation is ambiguous, with male and female characteristics combined in a single individual. In humans, well-characterized patients are 46, XY women who have the syndrome of pure gonadal dysgenesis, and a subset of true hermaphrodites are phenotypic men with a 46, XX karyotype. Analysis of such individuals has permitted identification of some of the molecules involved in sex determination, including SRY (sex-determining region Y gene), which is a Y chromosomal gene fulfilling the genetic and conceptual requirements of a testis-determining factor. The purpose of this review is to summarize the molecular basis for syndromes of sexual ambiguity seen in human patients and to identify areas where further research is needed. Understanding how sex-specific gene activity is orchestrated may provide insight into the molecular basis of other cell fate decisions during development which, in turn, may lead to an understanding of aberrant cell fate decisions made in patients with birth defects and during neoplastic change.

scholarly journals A genetic analysis of intersex, a gene regulating sexual differentiation in Drosophila melanogaster females.

Genetics ◽  
1995 ◽  
Vol 139 (4) ◽  
pp. 1649-1661 ◽  
Author(s):  
B A Chase ◽  
B S Baker
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Analysis ◽  
Sexual Differentiation ◽  
Point Mutations ◽  
Regulatory Genes ◽  
Sexually Dimorphic ◽  
Specific Product ◽  
Sex Type ◽  
A Cell ◽  
Female Specific

Abstract Sex-type in Drosophila melanogaster is controlled by a hierarchically acting set of regulatory genes. At the terminus of this hierarchy lie those regulatory genes responsible for implementing sexual differentiation: genes that control the activity of target loci whose products give rise to sexually dimorphic phenotypes. The genetic analysis of the intersex (ix) gene presented here demonstrates that ix is such a terminally positioned regulatory locus. The ix locus has been localized to the cytogenetic interval between 47E3-6 and 47F11-18. A comparison of the morphological and behavioral phenotypes of homozygotes and hemizygotes for three point mutations at ix indicates that the null phenotype of ix is to transform diplo-X animals into intersexes while leaving haplo-X animals unaffected. Analysis of X-ray induced, mitotic recombination clones lacking ix+ function in the abdomen of diplo-X individuals indicates that the ix+ product functions in a cell-autonomous manner and that it is required at least until the termination of cell division in this tissue. Taken together with previous analyses, our results indicate that the ix+ product is required to function with the female-specific product of doublesex to implement appropriate female sexual differentiation in diplo-X animals.

scholarly journals The role of the ovarian tumor locus in Drosophila melanogaster germ line sex determination

Development ◽  
1993 ◽  
Vol 119 (1) ◽  
pp. 123-134 ◽  
Author(s):  
D. Pauli ◽  
B. Oliver ◽  
A.P. Mahowald
Keyword(s):  
Drosophila Melanogaster ◽  
Sex Determination ◽  
Germ Cells ◽  
Ovarian Tumor ◽  
Germ Line ◽  
Gene Dosage ◽  
Constitutive Expression ◽  
Regulatory Cascade

The locus ovarian tumor (otu) is involved in several aspects of oogenesis in Drosophila melanogaster. The possible role of otu in the determination of the sexual identity of germ cells has not been extensively explored. Some otu alleles produce a phenotype known as ovarian tumors: ovarioles are filled with numerous poorly differentiated germ cells. We show that these mutant germ cells have a morphology similar to primary spermatocytes and that they express male germ line-specific reporter genes. This indicates that they are engaged along the male pathway of germ line differentiation. Consistent with this conclusion, we found that the splicing of Sex-lethal (Sxl) pre-mRNAs occurs in the male-specific mode in otu-transformed germ cells. The position of the otu locus in the regulatory cascade of germ line sex determination has been studied by using mutations that constitutively express the feminizing activity of the Sxl gene. The sexual transformation of the germ cells observed with several combinations of otu alleles can be reversed by constitutive expression of Sxl. This shows that otu acts upstream of Sxl in the process of germ line sex determination. Other phenotypes of otu mutations were not rescued by constitutive expression of Sxl, suggesting that several functions of otu are likely to be independent of sex determination. Finally, we show that the gene dosage of otu modifies the phenotype of ovaries heterozygous for the dominant alleles of ovo, another gene involved in germ line sex determination. One dose of otu+ enhances the ovoD ovarian phenotypes, while three doses partially suppress these phenotypes. Synergistic interaction between ovoD1 and otu alleles leads to the occasional transformation of chromosomally female germ cells into early spermatocytes. These interactions are similar to those observed between ovoD and one allele of the sans fille (snf) locus. Altogether, our results imply that the otu locus acts, along with ovo, snf, and Sxl, in a pathway (or parallel pathways) required for proper sex determination of the female germ line.

Androgen-induced plasticity at a “vocal” neuromuscular synapse

1994 ◽  
Vol 52 ◽  
pp. 32-33
Author(s):  
Darcy B. Kelley ◽  
Martha L. Tobias ◽  
Mark Ellisman
Keyword(s):  
Xenopus Laevis ◽  
Motor Neurons ◽  
Sexual Differentiation ◽  
Molecular Basis ◽  
Neuromuscular Synapse ◽  
Sexually Dimorphic ◽  
Intracellular Protein ◽  
Developmental Program ◽  
Androgen Action ◽  
Clawed Frog

Brain and muscle are sexually differentiated tissues in which masculinization is controlled by the secretion of androgens from the testes. Sensitivity to androgen is conferred by the expression of an intracellular protein, the androgen receptor. A central problem of sexual differentiation is thus to understand the cellular and molecular basis of androgen action. We do not understand how hormone occupancy of a receptor translates into an alteration in the developmental program of the target cell. Our studies on sexual differentiation of brain and muscle in Xenopus laevis are designed to explore the molecular basis of androgen induced sexual differentiation by examining how this hormone controls the masculinization of brain and muscle targets.Our approach to this problem has focused on a highly androgen sensitive, sexually dimorphic neuromuscular system: laryngeal muscles and motor neurons of the clawed frog, Xenopus laevis. We have been studying sex differences at a synapse, the laryngeal neuromuscular junction, which mediates sexually dimorphic vocal behavior in Xenopus laevis frogs.

scholarly journals GENETIC AND BIOCHEMICAL BASIS OF ENZYME ACTIVITY VARIATION IN NATURAL POPULATIONS. I. ALCOHOL DEHYDROGENASE IN DROSOPHILA MELANOGASTER

Genetics ◽  
1978 ◽  
Vol 89 (2) ◽  
pp. 371-388
Author(s):  
John F McDonald ◽  
Francisco J Ayala
Keyword(s):  
Gene Regulation ◽  
Drosophila Melanogaster ◽  
Alcohol Dehydrogenase ◽  
Natural Populations ◽  
Difficult Problem ◽  
Regulatory Genes ◽  
Biochemical Basis ◽  
Evolutionary Consequence ◽  
The Third ◽  
Adh Activity

ABSTRACT Recent studies by various authors suggest that variation in gene regulation may be common in nature, and might be of great evolutionary consequence; but the ascertainment of variation in gene regulation has proven to be a difficult problem. In this study, we explore this problem by measuring alcohol dehydrogenase (ADH) activity in Drosophila melanogaster strains homozygous for various combinations of given second and third chromosomes sampled from a natural population. The structural locus (Adh) coding for ADH is on the second chromosome. The results show that: (1) there are genes, other than Adh, that affect the levels of ADH activity; (2) at least some of these "regulatory" genes are located on the third chromosome, and thus are not adjacent to the Adh locus; (3) variation exists in natural populations for such regulatory genes; (4) the effect of these regulatory genes varies as they interact with different second chromosomes; (5) third chromosomes with high-activity genes are either partially or completely dominant over chromosomes with low-activity genes; (6) the effects of the regulatory genes are pervasive throughout development; and (7) the third chromosome genes regulate the levels of ADH activity by affecting the number of ADH molecules in the flies. The results are consistent with the view that the evolution of regulatory genes may play an important role in adaptation.

scholarly journals Extended Reproductive Roles of the fruitless Gene in Drosophila melanogaster Revealed by Behavioral Analysis of New fru Mutants

Genetics ◽  
1997 ◽  
Vol 147 (3) ◽  
pp. 1107-1130 ◽  
Author(s):  
Adriana Villella ◽  
Donald A Gailey ◽  
Barbra Berwald ◽  
Saiyou Ohshima ◽  
Phillip T Barnes ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Sex Determination ◽  
Molecular Genetics ◽  
Behavioral Analysis ◽  
Behavioral Phenotypes ◽  
New Mutations

The fruitless mutants fru3 and fru4 were assessed for sex-specific reproductive-behavioral phenotypes and compared to the previously reported fru mutants. Among the several behavioral anomalies exhibited by males expressing these relatively new mutations, some are unique. fru3 and fru4 males are less stimulated to court females than and fru1 and fru2. No courtship pulse song is generated by either fru3 or fru4 males, even though they perform brief wing extensions. fru3 and fru4 males display significantly less chaining behavior than do fru1 males. The hierarchy of courtship responses by fru males directed toward females vs. males, when presented with both sexes simultaneously, is that fru1 males perform vigorous and indiscriminant courtship directed at either sex; fru4 males are similarly indiscriminant, but courtship levels were lower than fru1; fru2 males prefer females; fru3 males show a courtship bias toward males. fru3 and fru4 males essentially lack the Muscle of Lawrence (MOL). On several reproductive criteria, there was no difference between fru-variant females and fru  +. The increases in phenotypic severity measured for the new mutants are discussed in the context of the emerging molecular genetics of fru and with regard to the gene's position within the sex-determination pathway.

Major sex-determining genes and the control of sexual dimorphism in Caenorhabditis elegans

Genome ◽  
1989 ◽  
Vol 31 (2) ◽  
pp. 625-637 ◽  
Author(s):  
Jonathan Hodgkin ◽  
Andrew D. Chisholm ◽  
Michael M. Shen
Keyword(s):  
Caenorhabditis Elegans ◽  
Sex Determination ◽  
X Chromosome ◽  
Germ Line ◽  
Cell Lineage ◽  
Regulatory Genes ◽  
Nematode Caenorhabditis Elegans ◽  
X Chromosomes ◽  
The Many ◽  
Lineage Analysis

Sex determination in Caenorhabditis elegans involves a cascade of major regulatory genes connecting the primary sex determining signal, X chromosome dosage, to key switch genes, which in turn direct development along either male or female pathways. Animals with one X chromosome (XO) are male, while animals with two X chromosomes (XX) are hermaphrodite: hermaphrodite development occurs because the action of the regulatory genes is modified in the germ line so that both sperm and oocytes are made inside a completely female soma. The regulatory genes are being examined by both genetic and molecular means. We discuss how these major genes, in particular the last switch gene in the cascade, tra-1, might regulate the many different sex-specific events that occur during the development of the hermaphrodite and of the male.Key words: nematode, Caenorhabditis elegans, sex determination, sexual differentiation, cell lineage analysis.

Sign in / Sign up

Export Citation Format

Share Document