A 14 bp promoter element directs the testis specificity of the Drosophila β2 tubulin gene (original) (raw)
Related papers
Nucleic Acids Research, 2000
The tissue-specific expression of the Drosophila β2 tubulin gene (B2t) is accomplished by the action of a 14-bp activator element (β2UE1) in combination with certain regulatory elements of the TATA-less, Inrcontaining B2t core promoter. We performed an in vivo analysis of the Inr element function in the B2t core promoter using a transgenic approach. Our experiments demonstrate that the Inr element acts as a functional cis-regulatory element in vivo and quantitatively regulates tissue-specific reporter expression in transgenic animals. However, our mutational analysis of the Inr element demonstrates no essential role of the Inr in mediating tissue specificity of the B2t promoter. In addition, a downstream element seems to affect promoter activity in combination with the Inr. In summary, our data show for the first time the functionality of the Inr element in an in vivo background situation in Drosophila.
MGG Molecular & General Genetics, 1993
Stem cell differentiation to mature spermatozoa is a morphogenetic process that is highly dependent on microtubular arrays. In the early, mitotically active stages of spermatogenesis, only the 131 tubulin isotype is expressed. Analysis of transgenic flies containing 131-lacZ gene fusions revealed that this expression is regulated by sequences located between positions -45 and -191 upstream of the transcription initiation site. Furthermore, 131 tubulin is a major component of cyst cells. Expression in these cells is driven by enhancer elements located in the [31 tubulin gene intron. These enhancer elements also guide expression in combination with the hsp70 basal promoter. In addition, redundant enhancer elements in the intron drive expression in the testis wall. Our data show that within a single tissue, the male gonad, expression of the [31 tubulin gene is under cell-type-specific control mediated by independent cis-acting elements. Therefore in the germ line, control of 131 tubulin expression is strictly governed by promoter-proximal elements, while for the somatic parts of the testis, enhancer elements confer less stringent expression control.
The beta 3-tubulin gene of Drosophila melanogaster is essential for viability and fertility
Genetics, 1991
We have previously shown that the P3-tubulin gene of Drosophila melanogaster encodes a divergent isoform expressed in a complex developmental pattern. The P3 gene is transiently expressed in the embryo and again in the pupa at high levels in the developing musculature, and at lower levels in several different pupal tissues of ectodermal origin. Adult expression is confined to specific somatic cells in the gonads. In some of the cell types in which it is expressed, P3 is the sole or predominant 8tubulin, while in others the 83 protein is a minor component of the P-tubulin pool. The sites and timing of P3 expression demonstrated that P3-tubulin is utilized primarily in cytoplasmic microtubule arrays involved in changes in cell shape and tissue organization, and suggested to us that this isoform may be functionally specialized. T o determine whether the expression of the P3 gene is essential for normal development, and to examine the specific functions of this divergent isoform, we have generated mutations within the gene. We determined that the small deficiency Df(2R)PxZ, which deletes the 60C5,6-60D9,10 region of chromosome 2, removes all of the P3 coding sequences, and that the distal breakpoint of the deficiency is approximately 2 kb upstream from the start of transcription of the 83 gene. We have generated a total of 31 ethyl methanesulfonate-or diepoxybutane-induced recessive lethal or visible mutations which map within the deficiency. These mutations define 12 new lethal complementation groups, which together with two previously identified visible mutations, altogether identify 14 genes in this interval of the second chromosome. A lethal complementation group comprising mutations in the P3-tubulin gene (PTub60D) was identified by rescue of their lethality by a wild-type copy of the gene introduced into the genome via P element-mediated germ line transformation. Analysis of the homozygous and transheterozygous phenotypes of the five 03 mutations recovered (alleles designated B?t'-B?t5) demonstrates that P3-tubulin is essential for viability and fertility.
Scientific Reports
Interspecific hybridization is a stressful condition that can lead to sterility and/or inviability through improper gene regulation in Drosophila species with a high divergence time. However, the extent of these abnormalities in hybrids of recently diverging species is not well known. Some studies have shown that in Drosophila, the mechanisms of postzygotic isolation may evolve more rapidly in males than in females and that the degree of viability and sterility is associated with the genetic distance between species. Here, we used transcriptomic comparisons between two Drosophila mojavensis subspecies and D. arizonae (repleta group, Drosophila) and identified greater differential gene expression in testes than in ovaries. We tested the hypothesis that the severity of the interspecies hybrid phenotype is associated with the degree of gene misregulation. We showed limited gene misregulation in fertile females and an increase in the amount of misregulation in males with more severe ste...
Mechanisms of Development, 1997
We identified and characterized the don juan gene (dj) of Drosophila melanogaster. The don juan gene codes for a sperm specific protein component with an unusual repetitive six amino acid motif (DPCKKK) in the carboxy-terminal part of the protein. The expression of Don Juan is limited to male germ cells where transcription of the dj gene is initiated during meiotic prophase. But Western blot experiments indicate that DJ protein occurs just postmeiotically. Examination of transgenic flies bearing a dj-promoter-lacZ reporter construct revealed lacZ mRNA distribution resembling the expression pattern of the endogenous dj mRNA in the adult testes, whereas /3-galactosidase expression is exclusively present in postmeiotic germ cells. Thus, these observations strongly suggest that dj transcripts are under translational repression until spermiogenesis. To study the function and subcellular distribution of DJ in spernliogenesis we expressed a chimaeric dj-GFP fusion gene in the male germline exhibiting strong GFP fluorescence in the live testes, where only elongated sperrnatids are decorated. With regard to the characteristic expression pattern of DJ protein and its conspicuous repeat units possible functional roles are discussed.
Retrogenes are functional processed copies of genes that originate via the retrotranscription of an mRNA intermediate and often exhibit testis-specific expression. Although this expression pattern appears to be favored by selection, the origin of such expression bias remains unexplained. Here, we study the regulation of two young testis-specific Drosophila retrogenes, Dntf-2r and Pros28.1A, using genetic transformation and the enhanced green fluorescent protein reporter gene in Drosophila melanogaster. We show that two different short (<24 bp) regions upstream of the transcription start sites (TSSs) act as testis-specific regulatory motifs in these genes. The Dntf-2r regulatory region is similar to the known b2 tubulin 14-bp testis motif (b2-tubulin gene upstream element 1 [b2-UE1]). Comparative sequence analyses reveal that this motif was already present before the Dntf-2r insertion and was likely driving the transcription of a noncoding RNA. We also show that the b2-UE1 occurs in the regulatory regions of other testis-specific retrogenes, and is functional in either orientation. In contrast, the Pros28.1A testes regulatory region in D. melanogaster appears to be novel. Only Pros28.1B, an older paralog of the Pros28.1 gene family, seems to carry a similar regulatory sequence. It is unclear how the Pros28.1A regulatory region was acquired in D. melanogaster, but it might have evolved de novo from within a region that may have been preprimed for testes expression. We conclude that relocation is critical for the evolutionary origin of male germline-specific cis-regulatory regions of retrogenes because expression depends on either the site of the retrogene insertion or the sequence changes close to the TSS thereafter. As a consequence we infer that positive selection will play a role in the evolution of these regulatory regions and can often act from the moment of the retrocopy insertion.