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Drosophila tan encodes a novel hydrolase required in pigmentation and vision.

True JR, Yeh SD, Hovemann BT, Kemme T, Meinertzhagen IA, Edwards TN, Liou SR, Han Q, Li J - PLoS Genet. (2005)

Bottom Line: We characterized two tan-like P-element insertions that failed to complement classical tan mutations.Both P insertions showed abnormally low transcription of the CG12120 mRNA.We conclude that D. melanogaster CG12120 corresponds to tan.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology and Evolution, State University of New York, Stony Brook, New York, United States of America. jrtrue@life.bio.sunysb.edu

ABSTRACT
Many proteins are used repeatedly in development, but usually the function of the protein is similar in the different contexts. Here we report that the classical Drosophila melanogaster locus tan encodes a novel enzyme required for two very different cellular functions: hydrolysis of N-beta-alanyl dopamine (NBAD) to dopamine during cuticular melanization, and hydrolysis of carcinine to histamine in the metabolism of photoreceptor neurotransmitter. We characterized two tan-like P-element insertions that failed to complement classical tan mutations. Both are inserted in the 5' untranslated region of the previously uncharacterized gene CG12120, a putative homolog of fungal isopenicillin-N N-acyltransferase (EC 2.3.1.164). Both P insertions showed abnormally low transcription of the CG12120 mRNA. Ectopic CG12120 expression rescued tan mutant pigmentation phenotypes and caused the production of striking black melanin patterns. Electroretinogram and head histamine assays indicated that CG12120 is required for hydrolysis of carcinine to histamine, which is required for histaminergic neurotransmission. Recombinant CG12120 protein efficiently hydrolyzed both NBAD to dopamine and carcinine to histamine. We conclude that D. melanogaster CG12120 corresponds to tan. This is, to our knowledge, the first molecular genetic characterization of NBAD hydrolase and carcinine hydrolase activity in any organism and is central to the understanding of pigmentation and photoreceptor function.

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P-Element Insertions in CG12120 Cause tan-Like Pigmentation Phenotypes and Ectopic Expression of CG12120 Rescues the tan Phenotype and Causes Ectopic Melanin Formation(A) The tan region of the D. melanogaster X chromosome. Known and predicted genes with directions of transcription are depicted below the line. Cytological divisions and flanking P-element insertions, as well as meiotic mapping data (see text), are indicated above the line.(B) Transcription unit of predicted gene CG12120. Boxes indicate exons. Black indicates coding region. Transcription start site, inferred from EST data [15], is at the position designated +1. Start codon is at position +250. Below are indicated positions of P{d07784} and P{g1557} insertions, just 3′ to the transcription initiation site (+1) of CG12120. Transcription unit is indicated in bold.(C–F) Adult (3–5 d) female body coloration of (C) CantonS (wild-type), (D) tan5, (E) w P{d07784}, and (F) w P{g1557}.(G and H) w tan1/w tan1; CyO/+; P{w+ C765-GAL4}/+ control female (G) and w tan1/w tan1; P{w+ UAS-CG12120}/+; P{ w+ C765-GAL4}/+ female (H) showing rescue of abdomen phenotype (arrows).(I and J) w/w; CyO/+; P{w+ pnr-GAL4}/+ control female (I) and w/w; P{w+ UAS-CG12120}/+; P{w+ pnr-GAL4}/+ female (J) showing ectopic melanin pattern along dorsal midline (arrowheads).All flies depicted were 3–5 d of age.
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pgen-0010063-g001: P-Element Insertions in CG12120 Cause tan-Like Pigmentation Phenotypes and Ectopic Expression of CG12120 Rescues the tan Phenotype and Causes Ectopic Melanin Formation(A) The tan region of the D. melanogaster X chromosome. Known and predicted genes with directions of transcription are depicted below the line. Cytological divisions and flanking P-element insertions, as well as meiotic mapping data (see text), are indicated above the line.(B) Transcription unit of predicted gene CG12120. Boxes indicate exons. Black indicates coding region. Transcription start site, inferred from EST data [15], is at the position designated +1. Start codon is at position +250. Below are indicated positions of P{d07784} and P{g1557} insertions, just 3′ to the transcription initiation site (+1) of CG12120. Transcription unit is indicated in bold.(C–F) Adult (3–5 d) female body coloration of (C) CantonS (wild-type), (D) tan5, (E) w P{d07784}, and (F) w P{g1557}.(G and H) w tan1/w tan1; CyO/+; P{w+ C765-GAL4}/+ control female (G) and w tan1/w tan1; P{w+ UAS-CG12120}/+; P{ w+ C765-GAL4}/+ female (H) showing rescue of abdomen phenotype (arrows).(I and J) w/w; CyO/+; P{w+ pnr-GAL4}/+ control female (I) and w/w; P{w+ UAS-CG12120}/+; P{w+ pnr-GAL4}/+ female (J) showing ectopic melanin pattern along dorsal midline (arrowheads).All flies depicted were 3–5 d of age.

Mentions: The tan locus was originally mapped to the cytological interval 8C3-9E3 by the inclusion of tan in Df(1)t282–1 [14]. We used meiotic mapping of local P-element insertions to determine that tan maps 0.51 cM proximal to P-element P{EPgy2}EY04394 (near CG12118) at position 8D1 and 0.51 cM distal to P-element P{EPgy2}EY05996 (near CG17754) at position 8D3 (Figure 1). This map interval contains 16 known or predicted genes. We subsequently obtained two new P insertions in this interval, P{d07784} [15] and P{g1557} [16], both of which were associated with a tan-like pigmentation phenotype (Figure 1E and 1F; compare with wild-type, Figure 1C, and tan mutant tan5, Figure 1D). One of these P inserts, P{d07784} was crossed with four classical tan mutants (tan1, tan2, tan4, and tan5) and failed to complement them for the pigmentation phenotype. These two P insertion lines were sequenced to determine the positions of the P insertions. In both lines, the P-element is inserted in the 5′ end of the first exon of predicted gene CG12120, at positions +9 and +21 bp, respectively (Figure 1B).


Drosophila tan encodes a novel hydrolase required in pigmentation and vision.

True JR, Yeh SD, Hovemann BT, Kemme T, Meinertzhagen IA, Edwards TN, Liou SR, Han Q, Li J - PLoS Genet. (2005)

P-Element Insertions in CG12120 Cause tan-Like Pigmentation Phenotypes and Ectopic Expression of CG12120 Rescues the tan Phenotype and Causes Ectopic Melanin Formation(A) The tan region of the D. melanogaster X chromosome. Known and predicted genes with directions of transcription are depicted below the line. Cytological divisions and flanking P-element insertions, as well as meiotic mapping data (see text), are indicated above the line.(B) Transcription unit of predicted gene CG12120. Boxes indicate exons. Black indicates coding region. Transcription start site, inferred from EST data [15], is at the position designated +1. Start codon is at position +250. Below are indicated positions of P{d07784} and P{g1557} insertions, just 3′ to the transcription initiation site (+1) of CG12120. Transcription unit is indicated in bold.(C–F) Adult (3–5 d) female body coloration of (C) CantonS (wild-type), (D) tan5, (E) w P{d07784}, and (F) w P{g1557}.(G and H) w tan1/w tan1; CyO/+; P{w+ C765-GAL4}/+ control female (G) and w tan1/w tan1; P{w+ UAS-CG12120}/+; P{ w+ C765-GAL4}/+ female (H) showing rescue of abdomen phenotype (arrows).(I and J) w/w; CyO/+; P{w+ pnr-GAL4}/+ control female (I) and w/w; P{w+ UAS-CG12120}/+; P{w+ pnr-GAL4}/+ female (J) showing ectopic melanin pattern along dorsal midline (arrowheads).All flies depicted were 3–5 d of age.
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Related In: Results  -  Collection

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pgen-0010063-g001: P-Element Insertions in CG12120 Cause tan-Like Pigmentation Phenotypes and Ectopic Expression of CG12120 Rescues the tan Phenotype and Causes Ectopic Melanin Formation(A) The tan region of the D. melanogaster X chromosome. Known and predicted genes with directions of transcription are depicted below the line. Cytological divisions and flanking P-element insertions, as well as meiotic mapping data (see text), are indicated above the line.(B) Transcription unit of predicted gene CG12120. Boxes indicate exons. Black indicates coding region. Transcription start site, inferred from EST data [15], is at the position designated +1. Start codon is at position +250. Below are indicated positions of P{d07784} and P{g1557} insertions, just 3′ to the transcription initiation site (+1) of CG12120. Transcription unit is indicated in bold.(C–F) Adult (3–5 d) female body coloration of (C) CantonS (wild-type), (D) tan5, (E) w P{d07784}, and (F) w P{g1557}.(G and H) w tan1/w tan1; CyO/+; P{w+ C765-GAL4}/+ control female (G) and w tan1/w tan1; P{w+ UAS-CG12120}/+; P{ w+ C765-GAL4}/+ female (H) showing rescue of abdomen phenotype (arrows).(I and J) w/w; CyO/+; P{w+ pnr-GAL4}/+ control female (I) and w/w; P{w+ UAS-CG12120}/+; P{w+ pnr-GAL4}/+ female (J) showing ectopic melanin pattern along dorsal midline (arrowheads).All flies depicted were 3–5 d of age.
Mentions: The tan locus was originally mapped to the cytological interval 8C3-9E3 by the inclusion of tan in Df(1)t282–1 [14]. We used meiotic mapping of local P-element insertions to determine that tan maps 0.51 cM proximal to P-element P{EPgy2}EY04394 (near CG12118) at position 8D1 and 0.51 cM distal to P-element P{EPgy2}EY05996 (near CG17754) at position 8D3 (Figure 1). This map interval contains 16 known or predicted genes. We subsequently obtained two new P insertions in this interval, P{d07784} [15] and P{g1557} [16], both of which were associated with a tan-like pigmentation phenotype (Figure 1E and 1F; compare with wild-type, Figure 1C, and tan mutant tan5, Figure 1D). One of these P inserts, P{d07784} was crossed with four classical tan mutants (tan1, tan2, tan4, and tan5) and failed to complement them for the pigmentation phenotype. These two P insertion lines were sequenced to determine the positions of the P insertions. In both lines, the P-element is inserted in the 5′ end of the first exon of predicted gene CG12120, at positions +9 and +21 bp, respectively (Figure 1B).

Bottom Line: We characterized two tan-like P-element insertions that failed to complement classical tan mutations.Both P insertions showed abnormally low transcription of the CG12120 mRNA.We conclude that D. melanogaster CG12120 corresponds to tan.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology and Evolution, State University of New York, Stony Brook, New York, United States of America. jrtrue@life.bio.sunysb.edu

ABSTRACT
Many proteins are used repeatedly in development, but usually the function of the protein is similar in the different contexts. Here we report that the classical Drosophila melanogaster locus tan encodes a novel enzyme required for two very different cellular functions: hydrolysis of N-beta-alanyl dopamine (NBAD) to dopamine during cuticular melanization, and hydrolysis of carcinine to histamine in the metabolism of photoreceptor neurotransmitter. We characterized two tan-like P-element insertions that failed to complement classical tan mutations. Both are inserted in the 5' untranslated region of the previously uncharacterized gene CG12120, a putative homolog of fungal isopenicillin-N N-acyltransferase (EC 2.3.1.164). Both P insertions showed abnormally low transcription of the CG12120 mRNA. Ectopic CG12120 expression rescued tan mutant pigmentation phenotypes and caused the production of striking black melanin patterns. Electroretinogram and head histamine assays indicated that CG12120 is required for hydrolysis of carcinine to histamine, which is required for histaminergic neurotransmission. Recombinant CG12120 protein efficiently hydrolyzed both NBAD to dopamine and carcinine to histamine. We conclude that D. melanogaster CG12120 corresponds to tan. This is, to our knowledge, the first molecular genetic characterization of NBAD hydrolase and carcinine hydrolase activity in any organism and is central to the understanding of pigmentation and photoreceptor function.

Show MeSH
Related in: MedlinePlus