A mouse atlas of gene expression: large-scale digital gene-expression profiles from precisely defined developing C57BL/6J mouse tissues and cells

Abstract

We analyzed 8.55 million LongSAGE tags generated from 72 libraries. Each LongSAGE library was prepared from a different mouse tissue. Analysis of the data revealed extensive overlap with existing gene data sets and evidence for the existence of approximately 24,000 previously undescribed genomic loci. The visual cortex, pancreas, mammary gland, preimplantation embryo, and placenta contain the largest number of differentially expressed transcripts, 25% of which are previously undescribed loci.

Fig. 1.

Differential expression of tag sequences among tissue groups. Shown is a graph of tag sequences at least 5-fold (red and yellow bars) and at least 10-fold (green and black bars) differentially expressed (P < 0.05 and P < 0.01, respectively) among tissue groups and all other libraries in all other tissue groups. The yellow and black bars depict the number of differentially expressed tag sequences that hit only unannotated regions of the genome sequence. The blue line indicates the number of libraries in each tissue group. From this data it is evident that the visual cortex, pancreas, mammary gland, preimplantation embryo, and placenta tissue groups contain the largest number of differentially expressed tag sequences, many of which hit unannotated regions of the genome. In contrast, virtually all of the differentially expressed tag sequences in stomach, spleen, and kidney hit annotated regions of the genome. SVZ/VZ, subventricular zones/ventricular zones; Post-I, post implantation; Pre-I, pre implantation; UGS, urogenital sinus.