Male-specific Fruitless isoforms have different regulatory roles conferred by distinct zinc finger DNA binding domains.
BACKGROUND
Drosophila melanogaster adult males perform an elaborate courtship ritual to entice females to mate. fruitless (fru), a gene that is one of the key regulators of male courtship behavior, encodes multiple male-specific isoforms (Fru(M)). These isoforms vary in their carboxy-terminal zinc finger domains, which are predicted to facilitate DNA binding.


RESULTS
By over-expressing individual Fru(M) isoforms in fru-expressing neurons in either males or females and assaying the global transcriptional response by RNA-sequencing, we show that three Fru(M) isoforms have different regulatory activities that depend on the sex of the fly. We identified several sets of genes regulated downstream of Fru(M) isoforms, including many annotated with neuronal functions. By determining the binding sites of individual Fru(M) isoforms using SELEX we demonstrate that the distinct zinc finger domain of each Fru(M) isoforms confers different DNA binding specificities. A genome-wide search for these binding site sequences finds that the gene sets identified as induced by over-expression of Fru(M) isoforms in males are enriched for genes that contain the binding sites. An analysis of the chromosomal distribution of genes downstream of Fru(M) shows that those that are induced and repressed in males are highly enriched and depleted on the X chromosome, respectively.


CONCLUSIONS
This study elucidates the different regulatory and DNA binding activities of three Fru(M) isoforms on a genome-wide scale and identifies genes regulated by these isoforms. These results add to our understanding of sex chromosome biology and further support the hypothesis that in some cell-types genes with male-biased expression are enriched on the X chromosome.
Biomedical Sciences Department and Program in Neuroscience, Florida State University, College of Medicine, Tallahassee, FL 32303, USA. michelle.arbeitman@med.fsu.edu.
Justin E
JE
Dalton
Justin M
JM
Fear
Simon
S
Knott
Bruce S
BS
Baker
Lauren M
LM
McIntyre
Michelle N
MN
Arbeitman
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D059006:Chromosomes, Insect / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D008297:Male; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012727:Sex Characteristics; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016335:Zinc Fingers
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D014157:Transcription Factors; C103226:fru protein, Drosophila