Temporal and spatial expression profiles of PRL/PL family members compared with phylogenetic tree analysis. A – Scale diagram of the PRL/PL gene locus on chromosome 13. Rectangles indicate the location of PRL family member genes and ovals represent the location of pseudogenes within the locus. Red arrows indicate the orientation of each gene within the cluster. Note the large inversion from Prl2b1 to Prl7c1. In addition, three Prl2c genes are located approximately 14 Mb upstream of the PRL/PL locus on chromosome 13. *The Prl2c gene located within the main prolactin family cluster (27–28 Mb) does not correspond to any of the 4 Prl2c genes previously annotated from cDNA sequences (Prl2c2-5) and is therefore referred to as Plf, the original gene symbol. B – Phylogenetic tree depicting the evolutionary relationship between the members of the PRL family coupled with temporal (northern blot analysis) and spatial (in situ hybridization summary) expression data for each gene. Blue boxes indicate some positive expression within the trophoblast subtype population while white boxes represent an absence of gene expression. **As the differences between the Prl2c genes (Prl2c2-5) cannot be discerned by northern blot analysis, the results in the current analysis reflect the combined expression of all these genes, and is therefore labeled simply as Prl2c.
Simmons et al. BMC Genomics 2008 9:352 doi:10.1186/1471-2164-9-352