epigenetics and imprinting Flashcards
what is epigenetics?
the study of additional information that is superimposed upon the nucleotide sequence of the DNA
this information takes the form of chemical groups attached to the DNA or attached to the histone proteins that the DNA is wrapped around
what enzymes are responsible for DNA methylation?
DNA methyltranferases
what enzyme removes methyl groups from DNA?
DNA demtheylases
what enzyme maintains methylation?
DNMT1
what is imprinting?
the process of epigenetic silencing in a parent of origin specific manner
for some genes only the paternal allele is active and for others it is only the maternal allele that is active
what does chromosome imprinting involve?
DNA methylation
histone modification
additional protein and RNA factors
what are the symptoms of Angelman syndrome?
delayed development severely mental retardation lack of speech microcephaly seizures ataxia
what is the genetic cause of Angelman syndrome?
no active UBE3A gene inherited from mother
maternal deletion at 15q11.2
what are the symptoms of Prada-Willi syndrome?
short stature
decrease in muscle tone
learning difficulties
what is the genetic cause of Prada-Willi syndrome?
no active SNRP and snoRNA genes inherited from father
paternal deletion at 15q11.2
what does UBE3A gene encode for?
a ubiquitin ligase
what does SNRP and snoRNA genes encode for?
protein products that play a role in RNA processing within the nucleus
