A set of highly conserved RNA-binding proteins, alphaCP-1 and alphaCP-2, implicated in mRNA stabilization, are coexpressed from an intronless gene and its intron-containing paralog.
Gene families normally expand by segmental genomic duplication and subsequent sequence divergence. Although copies of partially or fully processed mRNA transcripts are occasionally retrotransposed into the genome, they are usually nonfunctional ("processed pseudogenes"). The two major cytoplasmic poly(C)-binding proteins in mammalian cells, alphaCP-1 and alphaCP-2, are implicated in a spectrum of post-transcriptional controls. These proteins are highly similar in structure and are encoded by closely related mRNAs. Based on this close relationship, we were surprised to find that one of these proteins, alphaCP-2, was encoded by a multiexon gene, whereas the second gene, alphaCP-1, was identical to and colinear with its mRNA. The alphaCP-1 and alphaCP-2 genes were shown to be single copy and were mapped to separate chromosomes. The linkage groups encompassing each of the two loci were concordant between mice and humans. These data suggested that the alphaCP-1 gene was generated by retrotransposition of a fully processed alphaCP-2 mRNA and that this event occurred well before the mammalian radiation. The stringent structural conservation of alphaCP-1 and its ubiquitous tissue distribution suggested that the retrotransposed alphaCP-1 gene was rapidly recruited to a function critical to the cell and distinct from that of its alphaCP-2 progenitor.
Makeyev
A V
AV
Howard Hughes Medical Institute and the Departments of Genetics and Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.
Chkheidze
A N
AN
Liebhaber
S A
SA
D020413:3' Untranslated Regions / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins; D002460:Cell Line; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins; D019143:Evolution, Molecular; D005091:Exons; D018628:Gene Dosage; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007438:Introns; D051379:Mice; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D018626:Retroelements / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012261:Ribonucleoproteins / Q000737:chemistry / Q000235:genetics*; D016415:Sequence Alignment; D014157:Transcription Factors
D020413:3' Untranslated Regions; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D034441:Heterogeneous-Nuclear Ribonucleoproteins; C121375:Pcbp1 protein, mouse; C501904:Pcbp2 protein, mouse; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D018626:Retroelements; D012261:Ribonucleoproteins; D014157:Transcription Factors