New insulin-like growth factor (IGF)-precursor sequences from mammalian genomes: the molecular evolution of IGFs and associated peptides in primates

The complex genetics of human insulin-like growth factor 2 are not reflected in public databases

“…2C), which closely resembles IGF2 proteins found in other mammalian species (7,8). Once these mRNAs are translated, the 24-amino acid NH 2 -terminal signal peptide is co-translationally cleaved from the rest of the protein progenitor, and the 89-residue COOH-terminal E peptide is post-translationally processed to release fully bioactive 67-residue IGF2 (6, 31).…”

“…________________________________________ Insulin-like growth factor 2 (IGF2 1 ), a conserved 67-amino acid, single-chain secreted protein, is intimately involved in several critical physiological processes in humans and other mammals (1)(2)(3)(4)(5)(6). IGF2, along with IGF1 and insulin, also comprises a gene family that is found in most mammalian species (7)(8)(9). In humans, IGF2 plays a central role in normal pre-natal growth, and changes in its expression have been implicated in a variety of developmental growth syndromes (10,11).…”

Molecular evolution of the neurohypophysial hormone precursors in mammals: Comparative genomics reveals novel mammalian oxytocin and vasopressin analogues

“…In some cases sequence data were also available on the SRA database (http://trace.ncbi.nlm.nih.gov/Traces/sra) and were used to confirm or extend critical sequences. The quality and accuracy of the sequences used were assessed as in previous studies [31][32][33], by examining the available traces in detail and by comparison with previously available data, usually protein or cDNA sequence. Doubts about the validity of derived sequences are noted in Table 1, as are places where sequences were incomplete.…”

“…Analysis of separate parts of the precursor showed that the signal peptide shows a notably low dN/dS value of 0.075, much lower than that seen in many other signal sequences (c.f. insulin precursor, dN/dS = 0.32 for primates; TRH precursor, dN/dS = 0.34 for eutherian mammals [32,33]); the signal peptide may be conserved here because it is relatively short, and immediately followed by the biologically active neurohypophysial peptide. dN/dS is very low (0.009) for the sequence encoding OT, reflecting strong conservation.…”

Evolutionary genetics and implications of small size and twinning in callitrichine primates

“…In contrast, the largest of the tamarins, Leontopithecus, have a significantly shorter gestation period of ∼122 d (60). The fact that these two nonallometric changes are seen within the group points to the possibility of interesting evolutionary change in this trait (61).…”