scholarly journals The Drosophila melanogaster tropomyosin II gene produces multiple proteins by use of alternative tissue-specific promoters and alternative splicing.

1988 ◽  
Vol 8 (9) ◽  
pp. 3591-3602 ◽  
Author(s):  
P D Hanke ◽  
R V Storti
Keyword(s):  
Drosophila Melanogaster ◽  
Alternative Splicing ◽  
Gene Evolution ◽  
Cdna Clones ◽  
Developmentally Regulated ◽  
Dna Coding ◽  
Tropomyosin Isoforms ◽  
Alternatively Spliced ◽  
Transcriptional Units ◽  
Regulated Promoters

The structure of the Drosophila melanogaster tropomyosin II (TmII) gene has been determined by DNA sequencing of cDNA clones and the genomic DNA coding for the gene. Two overlapping transcriptional units produce at least four different tropomyosin isoforms. A combination of developmentally regulated promoters and alternative splicing produces both muscle and cytoskeletal tropomyosin isoforms. One promoter is a muscle-specific promoter and produces three different tropomyosin isoforms by alternative splicing of the last three 3' exons. The second promoter has the characteristics of a housekeeping promoter and produces a cytoskeletal tropomyosin isoform. Several internal exons along with a final 3' exon are alternatively spliced in the cytoskeletal transcript. The intron-exon boundaries of the TmII gene are identical to the intron-exon boundaries of all vertebrate tropomyosin genes reported, but are very different from the intron-exon boundaries of the D. melanogaster tropomyosin I gene. The TmII gene is the only reported tropomyosin gene that has two promoters and a quadruple alternative splice choice for the final exon. Models for the mechanism of D. melanogaster tropomyosin gene evolution are discussed.

The Drosophila melanogaster tropomyosin II gene produces multiple proteins by use of alternative tissue-specific promoters and alternative splicing

1988 ◽  
Vol 8 (9) ◽  
pp. 3591-3602
Author(s):  
P D Hanke ◽  
R V Storti
Keyword(s):  
Drosophila Melanogaster ◽  
Alternative Splicing ◽  
Gene Evolution ◽  
Cdna Clones ◽  
Developmentally Regulated ◽  
Dna Coding ◽  
Tropomyosin Isoforms ◽  
Alternatively Spliced ◽  
Transcriptional Units ◽  
Regulated Promoters

The structure of the Drosophila melanogaster tropomyosin II (TmII) gene has been determined by DNA sequencing of cDNA clones and the genomic DNA coding for the gene. Two overlapping transcriptional units produce at least four different tropomyosin isoforms. A combination of developmentally regulated promoters and alternative splicing produces both muscle and cytoskeletal tropomyosin isoforms. One promoter is a muscle-specific promoter and produces three different tropomyosin isoforms by alternative splicing of the last three 3' exons. The second promoter has the characteristics of a housekeeping promoter and produces a cytoskeletal tropomyosin isoform. Several internal exons along with a final 3' exon are alternatively spliced in the cytoskeletal transcript. The intron-exon boundaries of the TmII gene are identical to the intron-exon boundaries of all vertebrate tropomyosin genes reported, but are very different from the intron-exon boundaries of the D. melanogaster tropomyosin I gene. The TmII gene is the only reported tropomyosin gene that has two promoters and a quadruple alternative splice choice for the final exon. Models for the mechanism of D. melanogaster tropomyosin gene evolution are discussed.

scholarly journals Trans-acting Factors Required for Inclusion of Regulated Exons in the Ultrabithorax mRNAs of Drosophila melanogaster

Genetics ◽  
1999 ◽  
Vol 151 (4) ◽  
pp. 1517-1529 ◽  
Author(s):  
James M Burnette ◽  
Allyson R Hatton ◽  
A Javier Lopez
Keyword(s):  
Drosophila Melanogaster ◽  
Alternative Splicing ◽  
P Element ◽  
Splicing Factors ◽  
Loss Of Function ◽  
Large Collection ◽  
Splicing Pattern ◽  
Alternatively Spliced ◽  
Hypomorphic Alleles

Abstract Alternatively spliced Ultrabithorax mRNAs differ by the presence of internal exons mI and mII. Two approaches were used to identify trans-acting factors required for inclusion of these cassette exons. First, mutations in a set of genes implicated in the control of other alternative splicing decisions were tested for dominant effects on the Ubx alternative splicing pattern. To identify additional genes involved in regulation of Ubx splicing, a large collection of deficiencies was tested first for dominant enhancement of the haploinsufficient Ubx haltere phenotype and second for effects on the splicing pattern. Inclusion of the cassette exons in Ubx mRNAs was reduced strongly in heterozygotes for hypomorphic alleles of hrp48, which encodes a member of the hnRNP A/B family and is implicated in control of P-element splicing. Significant reductions of mI and mII inclusion were also observed in heterozygotes for loss-of-function alleles of virilizer, fl(2)d, and crooked neck. The products of virilizer and fl(2)d are also required for Sxl autoregulation at the level of splicing; crooked neck encodes a protein with structural similarities to yeast-splicing factors Prp39p and Prp42p. Deletion of at least five other loci caused significant reductions in the inclusion of mI and/or mII. Possible roles of identified factors are discussed in the context of the resplicing strategy for generation of alternative Ubx mRNAs.

scholarly journals Structure of transcripts from the homeotic Antennapedia gene of Drosophila melanogaster: two promoters control the major protein-coding region.

1986 ◽  
Vol 6 (12) ◽  
pp. 4676-4689 ◽  
Author(s):  
A Laughon ◽  
A M Boulet ◽  
J R Bermingham ◽  
R A Laymon ◽  
M P Scott
Keyword(s):  
Drosophila Melanogaster ◽  
Alternative Polyadenylation ◽  
Transcription Unit ◽  
Cdna Clones ◽  
Major Protein ◽  
Coding Region ◽  
Developmentally Regulated ◽  
Protein Coding ◽  
Reading Frame ◽  
C Terminus

The Antennapedia (Antp) homeotic gene of Drosophila melanogaster regulates segmental identity in the thorax. Loss of Antp function results in altered development of the embryonic thoracic segments or can cause legs to be transformed into antennae. Certain combinations of Antp recessive lethal alleles complement to permit normal development. The structure of the Antp gene, analyzed by sequencing cDNA clones and exons and by transcript mapping, revealed some of the basis for its genetic complexity. It has two promoters governing two nested transcription units, one unit 36 and one 103 kilobase pairs (kb) long. Both units incorporated the same protein-coding exons, all of which are located in the 3'-most 13 kb of the gene. The two promoters resulted in the attachment of either of two long noncoding leader sequences (1.5 and 1.7 kb) to a 1.1-kb open reading frame. Both transcription units used the same pair of alternative polyadenylation sites 1.4 kb apart; the choice of sites was developmentally regulated. Some of the mutations that disrupt the larger transcription unit complemented a mutation affecting the smaller one. Dominant mutations that transform antennae into legs split the gene but left the coding exons intact. The encoded protein has unusually long runs of glutamine and a homeodomain near the C terminus.

scholarly journals Evolutionary conservation of the structure and expression of alternatively spliced Ultrabithorax isoforms from Drosophila.

Genetics ◽  
1994 ◽  
Vol 136 (3) ◽  
pp. 965-977
Author(s):  
H M Bomze ◽  
A J López
Keyword(s):  
Alternative Splicing ◽  
Protein Function ◽  
Developmental Regulation ◽  
Expression Patterns ◽  
Proximal Region ◽  
Amino Acid Sequences ◽  
Drosophila Virilis ◽  
Protein Isoforms ◽  
Developmentally Regulated ◽  
Alternatively Spliced

Abstract In Drosophila melanogaster, alternatively spliced mRNAs from the homeotic gene Ultrabithorax (Ubx) encode a family of structurally distinct homeoprotein isoforms. The developmentally regulated expression patterns of these isoforms suggest that they have specialized stage- and tissue-specific functions. To evaluate the functional importance of UBX isoform diversity and gain clues to the mechanism that regulates processing of Ubx RNAs, we have investigated whether the Ubx RNAs of other insects undergo similar alternative splicing. We have isolated and characterized Ubx cDNA fragments from D. melanogaster, Drosophila pseudoobscura, Drosophila hydei and Drosophila virilis, species separated by as much as 60 million years of evolution, and have found that three aspects of Ubx RNA processing have been conserved. (1) These four species exhibit identical patterns of optional exon use in a region adjacent to the homeodomain. (2) These four species produce the same family of UBX protein isoforms with identical amino acid sequences in the optional exons, even though the common amino-proximal region has undergone substantial divergence. The nucleotide sequences of the optional exons, including third positions of rare codons, have also been conserved strongly, suggesting functional constraints that are not limited to coding potential. (3) The tissue- and stage-specific patterns of expression of different UBX isoforms are identical among these Drosophila species, indicating that the developmental regulation of the alternative splicing events has also been conserved. These findings argue for an important role of alternative splicing in Ubx function. We discuss the implications of these results for models of UBX protein function and the mechanism of alternative splicing.

Structure of transcripts from the homeotic Antennapedia gene of Drosophila melanogaster: two promoters control the major protein-coding region

1986 ◽  
Vol 6 (12) ◽  
pp. 4676-4689
Author(s):  
A Laughon ◽  
A M Boulet ◽  
J R Bermingham ◽  
R A Laymon ◽  
M P Scott
Keyword(s):  
Drosophila Melanogaster ◽  
Alternative Polyadenylation ◽  
Transcription Unit ◽  
Cdna Clones ◽  
Major Protein ◽  
Coding Region ◽  
Developmentally Regulated ◽  
Protein Coding ◽  
Reading Frame ◽  
C Terminus

The Antennapedia (Antp) homeotic gene of Drosophila melanogaster regulates segmental identity in the thorax. Loss of Antp function results in altered development of the embryonic thoracic segments or can cause legs to be transformed into antennae. Certain combinations of Antp recessive lethal alleles complement to permit normal development. The structure of the Antp gene, analyzed by sequencing cDNA clones and exons and by transcript mapping, revealed some of the basis for its genetic complexity. It has two promoters governing two nested transcription units, one unit 36 and one 103 kilobase pairs (kb) long. Both units incorporated the same protein-coding exons, all of which are located in the 3'-most 13 kb of the gene. The two promoters resulted in the attachment of either of two long noncoding leader sequences (1.5 and 1.7 kb) to a 1.1-kb open reading frame. Both transcription units used the same pair of alternative polyadenylation sites 1.4 kb apart; the choice of sites was developmentally regulated. Some of the mutations that disrupt the larger transcription unit complemented a mutation affecting the smaller one. Dominant mutations that transform antennae into legs split the gene but left the coding exons intact. The encoded protein has unusually long runs of glutamine and a homeodomain near the C terminus.

Conserved alternative splicing patterns and splicing signals in the Drosophila sodium channel gene para.

Genetics ◽  
1995 ◽  
Vol 141 (1) ◽  
pp. 203-214 ◽  
Author(s):  
J R Thackeray ◽  
B Ganetzky
Keyword(s):  
Alternative Splicing ◽  
Sodium Channel ◽  
Genomic Dna ◽  
Specific Pattern ◽  
Drosophila Virilis ◽  
Cdna Clones ◽  
Developmentally Regulated ◽  
Gene Encoding ◽  
Partial Cdna ◽  
Site Consensus

Abstract We cloned genomic DNA corresponding to the Drosophila virilis homologue of para, a gene encoding a sodium channel alpha-subunit, and obtained many partial cDNA clones from embryos and adults. Para protein has been well conserved, and the optional elements at six different sites of alternative splicing in D. melanogaster are present in D. virilis, in addition to one new optional exon. Among 31 different splice-types observed in D. virilis, the stage-specific pattern of alternative splicing seen in D. melanogaster is also conserved. Comparison of genomic DNA sequence revealed three aspects that vary between alternatively and constitutively used exon sequences. Sixteen short blocks (10-75 bp), the only recognizably conserved intron sequence, were disproportionately associated with alternatively used splice sites. Silent site substitutions were found much less frequently in alternative than constitutive exon elements, and the degree of match to the Drosophila splice site consensus tended to be lower at less frequently selected alternative splice junctions. This study shows that the developmentally regulated variability of para products is highly conserved and therefore likely to be of functional significance and suggests that a variety of different sequence-dependent mechanisms may regulate this pattern of alternative splicing.

scholarly journals Alternative splicing of chicken fibronectin in embryos and in normal and transformed cells.

1987 ◽  
Vol 7 (12) ◽  
pp. 4297-4307 ◽  
Author(s):  
P A Norton ◽  
R O Hynes
Keyword(s):  
Alternative Splicing ◽  
Mrna Level ◽  
Receptor Expression ◽  
Transcriptional Level ◽  
Cdna Clones ◽  
Mrna Levels ◽  
Oncogenic Transformation ◽  
Rous Sarcoma ◽  
Alternatively Spliced ◽  
V Region

To study the alternative splicing of fibronectin during embryogenesis and oncogenic transformation, we isolated cDNA clones of chicken fibronectin. The partial amino acid sequence deduced from sequencing of these clones showed that, overall, chicken fibronectin is approximately 80% identical with mammalian fibronectins. However, two of the three known regions of alternative splicing differed from this average. The V region was significantly more divergent, and RNA from embryonic chicken liver showed a pattern of V exon splicing which was distinct from that seen in human or rat fibronectins. In contrast, the EIIIB segment was very highly conserved (96%). As in mammals, this segment and another (EIIIA) were alternatively spliced in a cell-type-specific fashion. EIIIA+ and EIIIB+ species were almost absent in liver but predominated in total embryo RNA at all times from 2.5 to 11 days postfertilization. We also examined the possible contributions of fibronectin splicing and integrin receptor expression to the loss of fibronectin on oncogenic transformation. We detected little change in fibronectin splicing, other than a slight increase in representation of EIIIB+ species in fibroblasts after transformation by Rous sarcoma virus. It was also established that the overall reduction in fibronectin mRNA level observed after transformation was not accompanied by a decrease in integrin mRNA levels, indicating that fibronectin and integrin receptors are not coordinately regulated at the transcriptional level.

scholarly journals Functional Differences in Ionic Regulation between Alternatively Spliced Isoforms of the Na+-Ca2+ Exchanger from Drosophila melanogaster

1998 ◽  
Vol 111 (5) ◽  
pp. 691-702 ◽  
Author(s):  
Alexander Omelchenko ◽  
Christopher Dyck ◽  
Mark Hnatowich ◽  
John Buchko ◽  
Debora A. Nicoll ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Alternative Splicing ◽  
Xenopus Laevis Oocytes ◽  
Patch Clamp Technique ◽  
Inactive State ◽  
Functional Differences ◽  
Dependent Inactivation ◽  
Current Voltage ◽  
Alternatively Spliced ◽  
Regulatory Properties

Ion transport and regulation were studied in two, alternatively spliced isoforms of the Na+-Ca2+ exchanger from Drosophila melanogaster. These exchangers, designated CALX1.1 and CALX1.2, differ by five amino acids in a region where alternative splicing also occurs in the mammalian Na+-Ca2+ exchanger, NCX1. The CALX isoforms were expressed in Xenopus laevis oocytes and characterized electrophysiologically using the giant, excised patch clamp technique. Outward Na+-Ca2+ exchange currents, where pipette Ca2+o exchanges for bath Na+i, were examined in all cases. Although the isoforms exhibited similar transport properties with respect to their Na+i affinities and current–voltage relationships, significant differences were observed in their Na+i- and Ca2+i-dependent regulatory properties. Both isoforms underwent Na+i-dependent inactivation, apparent as a time-dependent decrease in outward exchange current upon Na+i application. We observed a two- to threefold difference in recovery rates from this inactive state and the extent of Na+i-dependent inactivation was approximately twofold greater for CALX1.2 as compared with CALX1.1. Both isoforms showed regulation of Na+-Ca2+ exchange activity by Ca2+i, but their responses to regulatory Ca2+i differed markedly. For both isoforms, the application of cytoplasmic Ca2+i led to a decrease in outward exchange currents. This negative regulation by Ca2+i is unique to Na+-Ca2+ exchangers from Drosophila, and contrasts to the positive regulation produced by cytoplasmic Ca2+ for all other characterized Na+-Ca2+ exchangers. For CALX1.1, Ca2+i inhibited peak and steady state currents almost equally, with the extent of inhibition being ≈80%. In comparison, the effects of regulatory Ca2+i occurred with much higher affinity for CALX1.2, but the extent of these effects was greatly reduced (≈20–40% inhibition). For both exchangers, the effects of regulatory Ca2+i occurred by a direct mechanism and indirectly through effects on Na+i-induced inactivation. Our results show that regulatory Ca2+i decreases Na+i-induced inactivation of CALX1.2, whereas it stabilizes the Na+i-induced inactive state of CALX1.1. These effects of Ca2+i produce striking differences in regulation between CALX isoforms. Our findings indicate that alternative splicing may play a significant role in tailoring the regulatory profile of CALX isoforms and, possibly, other Na+-Ca2+ exchange proteins.

scholarly journals Molecular cloning and heterologous expression of an alternatively spliced human Mu class glutathione S-transferase transcript

1993 ◽  
Vol 294 (2) ◽  
pp. 373-380 ◽  
Author(s):  
V L Ross ◽  
P G Board
Keyword(s):  
Alternative Splicing ◽  
Evolutionary Process ◽  
Complete Sequence ◽  
Human Testis ◽  
Cdna Clones ◽  
Glutathione S Transferase ◽  
Testis Cdna Library ◽  
Alternatively Spliced ◽  
Testis Cdna ◽  
Illegitimate Transcription

Two cDNA clones encoding a new Mu class glutathione S-transferase (GST) have been isolated from a human testis cDNA library. Both clones are incomplete and appear to result from alternative splicing. One clone is missing the sequence encoding exon 4 and the other is missing exon 8. The complete sequence of the previously undescribed isoenzyme can be deduced from the two cDNA clones. This is the first report of alternative splicing in a GST transcript and may represent either a novel form of regulation in this multigene family or illegitimate transcription and experimental alternative splicing as part of the evolutionary process. By combining components from each clone a complete cDNA has been constructed and the encoded protein expressed in Escherichia coli. In general, the recombinant enzyme has relatively low activity when compared with all the previously described human Mu class GST isoenzymes.

scholarly journals Profilin II Is Alternatively Spliced, Resulting in Profilin Isoforms That Are Differentially Expressed and Have Distinct Biochemical Properties

2000 ◽  
Vol 20 (21) ◽  
pp. 8209-8219 ◽  
Author(s):  
Anja Lambrechts ◽  
Attila Braun ◽  
Veronique Jonckheere ◽  
Attila Aszodi ◽  
Lorene M. Lanier ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Alternative Splicing ◽  
Expression Patterns ◽  
Biochemical Properties ◽  
Adult Brain ◽  
Developmentally Regulated ◽  
Alternatively Spliced ◽  
Minor Form ◽  
A Minor

ABSTRACT We deduced the structure of the mouse profilin II gene. It contains five exons that can generate four different transcripts by alternative splicing. Two transcripts encode different profilin II isoforms (designated IIa and IIb) that have similar affinities for actin but different affinities for polyphosphoinositides and proline-rich sequences. Profilins IIa and IIb are also present in humans, suggesting that all mammals have three profilin isoforms. Profilin I is the major form in all tissues, except in the brain, where profilin IIa is most abundant. Profilin IIb appears to be a minor form, and its expression is restricted to a limited number of tissues, indicating that the alternative splicing is tightly regulated. Western blotting and whole-mount in situ hybridization show that, in contrast to the expression of profilin I, the expression level of profilin IIa is developmentally regulated. In situ hybridization of adult brain sections reveals overlapping expression patterns of profilins I and IIa.

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