Gamma protocadherin gene cluster

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The gene cluster of the gamma protocadherins is located in humans on chromosome 5q in a region that has been identified as a predisposition to schizophrenia . Through different promoter activity upstream of each variable exon and alternative splicing to the three C-terminal , invariant exons, 22 different isoforms can be formed. In cell aggregation assays (experiments to measure cell contacts ) it could be shown that the respective isoforms enter into specific, homophilic interactions . The formation of tetramers from the 22 isoforms even increased the number of possible interaction surfaces from 22 to 22 4 or 234,256. The strong expression of the gamma protocadherins at the synapses of the central nervous system suggests an important function in the development of synaptic specificity. To date, however, there is no in vivo evidence that the gamma protocadherins are involved in the formation of specific cell-cell contacts .

Protocadherin family

The protocadherin family consists of three adjacent tandem-arrayed gene clusters which code for transmembrane proteins that are equipped with an N-terminal cadherin-like domain. Due to the localization at the synapses of the central nervous system, it was initially concluded that they were involved in the formation of the synapses or the formation of the synaptic specificity. The three gene clusters alpha. beta. gamma. are on chromosome 18 in mice and on chromosome 5q in humans that has been identified as a genetic predisposition to schizophrenia. The genomic organization of these genes seems unusual at first and is reminiscent of the arrangement of the immunoglobulin and T cell receptors.

Individual evidence

  1. ↑ A. Chess: Monoallelic expression of protocadherin genes. In: Nature Genetics . Volume 37, Number 2, 2005, pp. 120-121.
  2. ↑ T. Yagi: Clustered protocadherin family develop. In: Growth Differ. 50, 2008, pp. S131-S140
  3. ^ CM Lewis et al: Genome Scan Meta-Analysis of Schizophrenia and Bipolar Disorder, Part II: Schizophrenia. In: Am. J. Hum. Genet. 73, 2003, pp. 34-48.
  4. ↑ A. Chess: Monoallelic expression of protocadherin genes. In: Nature Genetics. Volume 37, Number 2, 2005, pp. 120-121.