A comparative genomic analysis of targets of Hox protein Ultrabithorax amongst distant insect species.
In the fruitfly Drosophila melanogaster, the differential development of wing and haltere is dependent on the function of the Hox protein Ultrabithorax (Ubx). Here we compare Ubx-mediated regulation of wing patterning genes between the honeybee, Apis mellifera, the silkmoth, Bombyx mori and Drosophila. Orthologues of Ubx are expressed in the third thoracic segment of Apis and Bombyx, although they make functional hindwings. When over-expressed in transgenic Drosophila, Ubx derived from Apis or Bombyx could suppress wing development, suggesting evolutionary changes at the level of co-factors and/or targets of Ubx. To gain further insights into such events, we identified direct targets of Ubx from Apis and Bombyx by ChIP-seq and compared them with those of Drosophila. While majority of the putative targets of Ubx are species-specific, a considerable number of wing-patterning genes are retained, over the past 300 millions years, as targets in all the three species. Interestingly, many of these are differentially expressed only between wing and haltere in Drosophila but not between forewing and hindwing in Apis or Bombyx. Detailed bioinformatics and experimental validation of enhancer sequences suggest that, perhaps along with other factors, changes in the cis-regulatory sequences of earlier targets contribute to diversity in Ubx function.
Indian Institute of Science Education and Research Pune, 411008, India.
Naveen
N
Prasad
Indian Institute of Science Education and Research Pune, 411008, India.
Shreeharsha
S
Tarikere
Indian Institute of Science Education and Research Pune, 411008, India.
Dhanashree
D
Khanale
Indian Institute of Science Education and Research Pune, 411008, India.
Farhat
F
Habib
Indian Institute of Science Education and Research Pune, 411008, India.
L S
LS
Shashidhara
D000818:Animals; D030801:Animals, Genetically Modified; D001516:Bees; D005075:Biological Evolution; D012831:Bombyx; D055028:Comparative Genomic Hybridization; D019295:Computational Biology; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D038081:Organogenesis; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics*; D013045:Species Specificity; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014921:Wings, Animal / Q000502:physiology*
D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D014157:Transcription Factors; C066177:Ubx protein, Drosophila