Hypothesis :
Hypothesis There are regulatory sequences in gene deserts that are responsible for the complex expression of the DACH gene in humans.
Background :
Background Gene Desert – gene-poor region greater than 500 kb
25% of human genome consists of gene deserts
DACH gene is expressed in numerous tissues, and is involved in development of brain, limbs, and sensory organs
DACH gene is 430 kb and is bracketed by 2 gene deserts 870 kb and 1330 kb
TATA Box – Part of the promoter sequence in transcription and is located about 10bp from the starting point
Introns – Must be excised from pre-mRNA to generate a mature mRNA that can be translated into a complete polypeptide
Experiment :
Experiment Compared DACH sequence and gene deserts to mouse DACH sequence
Also compared to frog, zebrafish, and 2 pufferfish
Found 32 conserved sequences
Tested to see if these 32 sequences represent enhancers
Experiment Continued :
Experiment Continued Tested 9 elements from the 2 gene deserts and DACH’s introns
Cloned the elements upstream of heat shock protein 68 minimal promoter coupled to ß-galactosidase
Injected clones into fertilized mouse oocytes
Results and Conclusions :
Results and Conclusions 7 of the 9 elements were shown to drive ß-galactosidase in certain tissues
Many of these enhancers reside in gene deserts
Shows good support that gene deserts can serve as reservoirs for these long range enhancers
Size of genomic regions that are linked to the expression of a gene should be expanded to include much larger regions than originally believed