Fig. 5

Proof of concept of four "hidden" chicken genes. a After obtaining the complete coding sequence we assessed by quantitative PCR the expression profiles of muscle-type aldolase (ALDOA), enolase (ENO3), glycogen phosphorylase (PYGM), and glucose transporter (GLUT4). Expression signals were normalized against ribosomal protein gene RPS13 [74] and calculated relative to the expression ratio in pectoralis muscle. b Western blot of immunoreactive GLUT4 using protein extracts from the same tissue panel as for the mRNA analysis. Lower panel shows abundance of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). c and d Schematic representation of human (c) and chicken (d) GLUT4 primary structure in a model of 12 transmembrane helices that surround the water-filled glucose diffusion pore [23]. Small circles, identical residues in both species; green, one of the following four amino acids (GARP) encoded by GC-rich codons. Residues that are important for sugar binding and transport and for GLUT4 recycling are conserved (violet and pink circles). e Counts (%) of glycine, alanine, arginine and proline in membrane and non-membrane parts in the human and chicken GLUT4. The avian increase in GARP is not random. For instance, the number of helix-disrupting prolines only rise in the non-membrane segments of the protein