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Figure 6 | BMC Molecular Biology

Figure 6

From: Structure and expression of two nuclear receptor genes in marsupials: insights into the evolution of the antisense overlap between the α-thyroid hormone receptor and Rev-erbα

Figure 6

Models for the evolution of antisense exon 10 in TRα and expression of the TRα2 isoform. Three models are proposed for the evolution of the TRα2 isoform and its antisense overlap with Rev-erbα. In the first model (TRα2 "late"), alternatively spliced TRα2 mRNA evolved only after the divergence of marsupial and eutherian mammals so that TRα2 is unique to eutherian mammals. In the second model (TRα2 "early"), a functional but primitive version of TRα2 (uTRα2) evolved early in the course of mammalian evolution, but in marsupials the modern, truncated form of TRα2 (tTRα2) is expressed only at very low levels or its expression is temporally or spatially restricted. In the third model (TRα2 "lost"), a functional version of TRα2 (uTRα2) evolved very early in the common ancestor of marsupial and eutherian mammals, but this alternative isoform was lost at some later time in marsupial lineage.

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BMC Molecular Biology

ISSN: 1471-2199

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