Novel cuticular proteins revealed by the honey bee genome.
With the completion of the honey bee genome project, a transition is now occurring from the acquisition of gene sequence to understanding the role and context of gene products within the genome. Here we annotated and characterised a cluster of three genes in a GC-rich 11 kb genomic region on the linkage group 4 encoding highly hydrophobic polypeptides (named apidermins; APD 1-3) containing both sequence motifs characteristic of cuticular proteins and distinctly novel features. Five amino acids, Ala, Gly, Leu, Pro and Val, account for 74-86% of their respective sequences with Ala being the most abundant residue (at least 30% of each peptide). A conserved tetra-peptide AAPA/V is found in all three proteins, but none has the 'R and R' signature implicated in chitin binding. Two proteins, APD-1 and APD-2, contain an arginine-rich motif RERR in short non-hydrophobic stretches near the N-terminal of mature proteins and in both proteins tryptophan is the C-terminal residue. All three genes are spliced and highly expressed in a defined spatio-temporal pattern. apd-1 is expressed in the exoskeletal epidermis, but only during a restricted period of a few days of late pupal and early adult life when the cuticle becomes dark. APD2 appears to be a protein of "internal" cuticles and is expressed in the tracheas, oesophagus and stomach, and also in the embryo. The expression of apd-3 partly overlaps with both apd-1 and apd-3, but apd-3 also is uniquely associated with non-pigmented cuticles such as the eye cover and external cuticle of white pupae. This study expands the collection of genes encoding cuticular proteins by three novel and well characterised members.
Kucharski
R
R
ARC Centre for the Molecular Genetics of Development and Visual Sciences, Research School of Biological Sciences, The Australian National University, Canberra, ACT 0200, Australia.
Maleszka
J
J
Maleszka
R
R
D000595:Amino Acid Sequence; D000818:Animals; D001516:Bees / Q000235:genetics / Q000378:metabolism*; D005075:Biological Evolution; D015870:Gene Expression; D020869:Gene Expression Profiling; D015723:Gene Library; D049750:Genome, Insect; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data
D019476:Insect Proteins; C047663:cuticle proteins, insects