Human A-myb gene encodes a transcriptional activator containing the negative regulatory domains

AbstractThe myb gene family has three members, c-myb, A-myb, and B-myb. A-myb mRNA is mainly expressed in testis and peripheral blood leukocytes. A-Myb can activate transcription from the promoter containing Myb-binding sites in all cells examined. In addition to the two domains (a DNA-binding domain and a transcriptional activation domain), two negative regulatory domains have been identified in A-Myb. These results indicate that A-Myb functions as a transcriptional activator mainly in testis and peripheral blood cells, and the regulatory mechanism of A-Myb activity is similar to that of c-Myb

Defective proventriculus specifies the ocellar region in the Drosophila head

A pair of the Drosophila eye-antennal disc gives rise to four distinct organs (eyes, antennae, maxillary palps, and ocelli) and surrounding head cuticle. Developmental processes of this imaginal disc provide an excellent model system to study the mechanism of regional specification and subsequent organogenesis. The dorsal head capsule (vertex) of adult Drosophila is divided into three morphologically distinct subdomains: ocellar, frons, and orbital. The homeobox gene orthodenticle (otd) is required for head vertex development, and mutations that reduce or abolish ad expression in the vertex primordium lead to ocelliless flies. The homeodomain-containing transcriptional repressor Engrailed (En) is also involved in ocellar specification, and the En expression is completely lost in otd mutants. However, the molecular mechanism of ocellar specification remains elusive. Here, we provide evidence that the homeobox gene defective proventriculus (dye) is a downstream effector of Otd, and also that the repressor activity of Dye is required for en activation through a relief-of-repression mechanism. Furthermore, the Dye activity is involved in repression of the frons identity in an incoherent feedforward loop of Otd and Dye

The Homeodomain Protein Defective Proventriculus Is Essential for Male Accessory Gland Development to Enhance Fecundity in Drosophila

The Drosophila male accessory gland has functions similar to those of the mammalian prostate gland and the seminal vesicle, and secretes accessory gland proteins into the seminal fluid. Each of the two lobes of the accessory gland is composed of two types of binucleate cell: about 1,000 main cells and 40 secondary cells. A well-known accessory gland protein, sex peptide, is secreted from the main cells and induces female postmating response to increase progeny production, whereas little is known about physiological significance of the secondary cells. The homeodomain transcriptional repressor Defective proventriculus (Dve) is strongly expressed in adult secondary cells, and its mutation resulted in loss of secondary cells, mononucleation of main cells, and reduced size of the accessory gland. dve mutant males had low fecundity despite the presence of sex peptide, and failed to induce the female postmating responses of increased egg laying and reduced sexual receptivity. RNAi-mediated dve knockdown males also had low fecundity with normally binucleate main cells. We provide the first evidence that secondary cells are crucial for male fecundity, and also that Dve activity is required for survival of the secondary cells. These findings provide new insights into a mechanism of fertility/fecundity

Defective proventriculus specifies the ocellar region in the Drosophila head

A pair of the Drosophila eye-antennal disc gives rise to four distinct organs (eyes, antennae, maxillary palps, and ocelli) and surrounding head cuticle. Developmental processes of this imaginal disc provide an excellent model system to study the mechanism of regional specification and subsequent organogenesis. The dorsal head capsule (vertex) of adult Drosophila is divided into three morphologically distinct subdomains: ocellar, frons, and orbital. The homeobox gene orthodenticle (otd) is required for head vertex development, and mutations that reduce or abolish ad expression in the vertex primordium lead to ocelliless flies. The homeodomain-containing transcriptional repressor Engrailed (En) is also involved in ocellar specification, and the En expression is completely lost in otd mutants. However, the molecular mechanism of ocellar specification remains elusive. Here, we provide evidence that the homeobox gene defective proventriculus (dye) is a downstream effector of Otd, and also that the repressor activity of Dye is required for en activation through a relief-of-repression mechanism. Furthermore, the Dye activity is involved in repression of the frons identity in an incoherent feedforward loop of Otd and Dye

Measuring of some selected herbicides in paddy surface water in the Saijo Basin, Western Japan

An analysis of the dissipation of herbicides was done in paddy water and in drainage channels of farm paddies as well as in experimental plots. A field study was conducted in three selected paddy farms of Higashi Hiroshima and an experiment was carried out in the Hiroshima Prefecture Agriculture Research Center in the paddy season of the year 2002. The herbicides were mefenacet, thiobencarb, pyributicarb and cyhalofop –butyl. The sample water was analyzed by using gas chromatography after solid phase extraction. The maximum concentration of all herbicides was detected within 1 to 3 days after herbicide application and became trace level after 21 to 28 days. The highest amount of herbicide detected was 338 $\mu$g/L mefenacet in Farm B. No cyhalofop-butyl was detected in the experiment but was found in farm paddies until 7 days. Thiobencarb was detected until 21 and 28 days, respectively, in farm paddies and in the experiment. Pyributicarb was detected until 28 days in farm paddies and in the experiment. We found that the concentration of all herbicides in drainage channels was comparable with the paddy field at 1 day and 3 days and thiobencarb at 1 day