A 3.5-kb DNA fragment contains the cis-regulatory elements for retina-specific expression and partial dosage compensation of the Arrestin B (ArrB) gene of Drosophila miranda.
A 3.5-kb genomic DNA fragment containing the X1R chromosome-linked retina-specific Arrestin B gene (also called Arrestin 2) of Drosophila miranda (ArrB-mr) was introduced into the Drosophila melanogaster genome via germ-line transformation. The results showed that the ArrB-mr transgene was expressed only in the retina of the transformed flies. The transgene also showed male-specific transcriptional hyperactivation or dosage compensation, but the level was found to be 71-79% of the expected value. The endogenous autosomal ArrB-ml gene of D. melanogaster, as expected, was not found to be dosage compensated in the transformants. Thus, while the cis-regulatory elements for retina-specific expression are fully present in the 3.5-kb DNA, part of the sequences needed for full dosage compensation are missing in this DNA. Nucleotide (nt) sequence comparison of the upstream DNA revealed that both ArrB-mr and ArrB-ml possess a putative TATA box at -32 nt. They also have an 11-bp motif (5'-AATCCAGTTAG) similar to the photoreceptor conserved element I (PCE I) believed to play an important role in retina-specific expression of the D. melanogaster opsin and mouse Arr genes. In addition, both genes contain a TGACCT motif which is known to bind a transcription factor activated by retinoic acid and vitamin D3. However, five tandem repeats of a heptanucleotide sequence (TGGGCNR) and a 29-bp sequence with the potential to form a stem-loop structure, are found only in the ArrB-ml gene. These sequences may play an important role in dosage compensation of the X1R-linked ArrB-mr gene.
Krishnan
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R
Program in Cell, Molecular and Developmental Biology, University of Tennessee, Knoxville 37996, USA.
Ganguly
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R
D000818:Animals; D030801:Animals, Genetically Modified; D019390:Arrestins; D001483:Base Sequence; D002875:Chromosomes; D004247:DNA / Q000235:genetics*; D004303:Dosage Compensation, Genetic; D004330:Drosophila / Q000235:genetics* / Q000378:metabolism; D029721:Drosophila Proteins; D005136:Eye Proteins / Q000096:biosynthesis / Q000235:genetics*; D005260:Female; D005786:Gene Expression Regulation; D017344:Genes, Insect; D051379:Mice; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010750:Phosphoproteins / Q000096:biosynthesis / Q000235:genetics*; D017956:Photoreceptor Cells, Invertebrate / Q000737:chemistry; D012045:Regulatory Sequences, Nucleic Acid; D012160:Retina / Q000378:metabolism*; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D016385:TATA Box; D014960:X Chromosome
C504666:Arr2 protein, Drosophila; D019390:Arrestins; D029721:Drosophila Proteins; D005136:Eye Proteins; D010750:Phosphoproteins; D004247:DNA