Genes in Drosophila

Homeoboxes code for homeodomains, sequences of 60 amino acids that function as the DNA-binding regions of transcription factors. Each homeo-box gene in Drosophila is expressed only in its own characteristic subset of embryonic cells, and almost every embryonic cell contains a unique combination of homeodomain proteins. 

Figure 9.11 Amino acid sequences of homeodomains from four differenf franscription factors Anfp is from fhe Antennapedia gene in the fruitfly Drosophila, a2 is from the yeast Mat o2 gene, eng is from fhe engrailed gene in Drosophila and POU is from fhe POU homeodomain in the mammalian gene Oct-1. Residues colored green form the hydrophobic core of the homeodomain, blue form nonspecific interactions with the DNA backbone and red form contacts with the edges of the DNA bases.

Frizzled (Fz) proteins comprise a family of seven-pass transmembrane receptors with a cysteine-rich extracellular domain. As a class, Fz proteins are structurally related to the superfamily ofheterotrimeric G-protein coupled receptors (GPCRs). Diere are 4 Fz genes in Drosophila and 10 in humans, with close orthologs... 

There are 7 related Wnt genes in Drosophila and 19 in humans that generally have close orthologs in mice (Fig. 1). Orthologous Wnt gene-products are often very highly conserved between species. 

Ardell, D.H. and Andersen, S.O., Tentative identibcation of a resilin gene in Drosophila melanogaster. Insect Biochem. Mol. Biol., 31, 965-970, 2001. 

Harding, K., Wedeen, C., McGinnis, W and Levine, M. (1985). Spatially regulated expression of homeotic genes in Drosophila. Science 229 1236-1242. 

Azolides used as inhibitors for monoamine oxidase1171 or human leucocyte elastase,1181 as inductors of recessive lethal genes in Drosophila,1191 as histamine H2-receptor antagonists,1201 as anti-ulcer agents,1211 or as pharmacophores for anthelmintic, analgesic, and antimicrobial activity 1221... 

Tzou, P. et al., Tissue specific inducible expression of antimicrobial peptide genes in Drosophila surface epithelia. Immunity, 13, 737 2000. 

Szianka, T. et al. Deletion of proteasomal subunit S5a/Rpnl0/p54 causes lethality, multiple mitotic defects and overexpression of proteasomal genes in Drosophila melanogaster. / Cell Sci 2003, 116, 1023-33. 

Emx genes are important for the genesis of the hippocampus (Pellegrini et ah, 1996) and point mutations of Emx2 are associated with schizencephaly (Brunelli et ah, 1996). Thus, these homologues of early segmentation genes in Drosophila serve fundamental functions in the development in the human brain. 

Systematic functional analysis and mapping of X-chromosomal genes in Drosophila melanogaster H. Jackie, MPI for Biophysical Chemistry, Gottingen ... 

FIGURE 28-39 Effects of mutations in homeotic genes in Drosophila, (a) Normal head, (b) Homeotic mutant (antennapedia) in which antennae are replaced by legs, (c) Normal body structure, (d) Homeotic mutant (bithorax) in which a segment has developed incorrectly to produce an extra set of wings. 

Wicker-Thomas C., Henriet C. and Dallerac R. (1997) Partial characterization of a fatty acid desaturase gene in Drosophila melanogaster. Insect Biochem. Molec. Biol. 27, 963-972. 

The LINEs are much larger and seem to be derived from retroviral sequences. However, they do not have terminal repeats, and many of the elements found in the genome are truncated at the 5 end. Most SINEs and LINEs have a duplication of the genomic DNA at the insertion site. The LINEs generally have long open reading frames which share sequence similarity with retroviral genes. In Drosophila several middle repetitive LINE-like sequences have been characterized such as the I element, F element, and the ribosomal insertion sequences.20... 

---