Investigating gradients of gene expression involved in early human cortical development.
The division of the neocortex into functional areas (the cortical map) differs little between individuals, although brain lesions in development can lead to substantial re-organization of regional identity. We are studying how the cortical map is established in the human brain as a first step towards understanding this plasticity. Previous work on rodent development has identified certain transcription factors (e.g. Pax6, Emx2) expressed in gradients across the neocortex that appear to control regional expression of cell adhesion molecules and organization of area-specific thalamocortical afferent projections. Although mechanisms may be shared, the human neocortex is composed of different and more complex local area identities. Using Affymetrix gene chips of human foetal brain tissue from 8 to 12.5 post-conceptional weeks [PCW, equivalent to Carnegie stage (CS) 23, to Foetal stage (F) 4], human material obtained from the MRC-Wellcome Trust Human Developmental Biology Resource (http://www.hdbr.org), we have identified a number of genes that exhibit gradients along the anterior-posterior axis of the neocortex. Gene probe sets that were found to be upregulated posteriorally compared to anteriorally, included EMX2, COUPTFI and FGF receptor 3, and those upregulated anteriorally included cell adhesion molecules such as cadherins and protocadherins, as well as potential motor cortex markers and frontal markers (e.g. CNTNAP2, PCDH17, ROBO1, and CTIP2). Confirmation of graded expression for a subset of these genes was carried out using real-time PCR. Furthermore, we have established a dissociation cell culture model utilizing tissue dissected from anteriorally or posteriorally derived developing human neocortex that exhibits similar gradients of expression of these genes for at least 72 h in culture.
Ip
Bui K
BK
Institute of Human Genetics, Newcastle University, Newcastle upon Tyne, UK.
Wappler
Ilka
I
Peters
Heiko
H
Lindsay
Susan
S
Clowry
Gavin J
GJ
Bayatti
Nadhim
N
D000818:Animals; D001931:Brain Mapping / Q000379:methods; D051838:COUP Transcription Factor I / Q000235:genetics; D015820:Cadherins / Q000235:genetics; D015815:Cell Adhesion Molecules / Q000235:genetics* / Q000378:metabolism; D005346:Fibroblast Growth Factors / Q000235:genetics; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D018398:Homeodomain Proteins / Q000235:genetics; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics; D046228:Microarray Analysis; D019579:Neocortex / Q000196:embryology* / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D011971:Receptors, Immunologic / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012377:Rodentia / Q000196:embryology / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000235:genetics; D015854:Up-Regulation / Q000235:genetics; D000097905:Roundabout Proteins; D000099260:Empty Spiracles Homeobox Proteins
D051838:COUP Transcription Factor I; D015820:Cadherins; D015815:Cell Adhesion Molecules; D005346:Fibroblast Growth Factors; D018398:Homeodomain Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D011971:Receptors, Immunologic; D012097:Repressor Proteins; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D000097905:Roundabout Proteins; D000099260:Empty Spiracles Homeobox Proteins; C479740:BCL11B protein, human; C403049:CNTNAP2 protein, human; C529349:PCDH17 protein, human