Epigenetics Flashcards
topics under current investigation:
- short term memory (sec-hrs)
- long term memory (decades)
- trauma
- children’s aggression
- drug addiction
- depression
- suicide
who attends conferences on epigenetics & behavior?
- anthropologists
- geneticists
- neuroscientists
- molecular bioligists
- psychiatrists
- psychologists
what is epigenetics? (old definition)
-heritable changes in a phenotype in the absence of alterations of the DNA sequence
new definition of epigenetics:
-any lasting change in gene expression mediated by alteration in chromatin structure
chromatin=
-DNA plus proteins
what is gene expression?
- transcription of DNA code in RNA by RNA polymerase (mRNA, tRNA, rRNA, microRNA)
- translation of mRNA into proteins
what controls gene expression?
- proteins can change the shape of the DNA, making some regions of DNA available for transcription and some unavailable
- histones, non-histone proteins & transcription factors
what are histones?
- proteins that DNA is wrapped around.
- they can make DNA available or unavailable for transcription
what are transcription factors?
-proteins that can bind to DNA at promoter and enhancer sites (noncoding DNA regions) and alter the shape of DNA
alteration of gene expression causes=
-cell differentiation
what regulates transcription factors activity?
- many primary messenger molecules such as: NP, hormones & cytokines, regulate gene transcription
- some, such as steroid hormones bind directly to transcription regulating proteins (aka->hormone receptors) that bind to regions of DNA called hormone response elements
regulation of transcription factors thru phosphorylation:
- other primary messengers regulate phosphorylation of transcription factors by activating protein kinases that phosphorylate the transcription factors
- i.e. regulation of gene expression by cyclic AMP
regulation of phosphorylation by receptors with tyrosine kinase activity:
-many growth factors as well as insulin influence cells this way
the roles of non-coding DNA:
- noncoding DNA=DNA that is not transcribed to RNA=90% of human genome
- sites for the binding of transcription factors
- after binding transcription factors, the DNA can fold or unfold in various ways that influence the availability of a coding region of DNA for transcription to RNA
mutations of noncoding DNA regions can lead to disease without a mutation of a known gene:
- noncoding DNA mutations have been found that increase a person’s risk for developing:
- coronary artery disease
- cancer: prostate, colorectal
- extra fingers & toes
- excessive inflammation
