Stupid fucking genetics exam 4

gene regulation

how a cell controls which genes, out of the many genes in its genome, are expressed

transcription activator proteins

increases transcription of a gene or set of genes

Methylation of CpG island

stably silences genes

enhancers

cis-acting DNA sequences that can increase the transcription of genes

activator

a protein (transcription factor) that increases transcription of a gene or set of genes.

silencer

regulatory DNA elements that reduce transcription from their target promoters

mediator

A complex of proteins that allows initiation of cell- and/or cell cycle-specific control of eukaryotic transcription

transcription factors

proteins that regulate the transcription of genes

siRNA

a double-stranded RNA molecule that is non-coding

miRNA

approximately 22 nucleotide long, small noncoding RNAs that function in posttranscriptional gene silencing

RISCS

a multiprotein complex that incorporates one strand of a small interfering RNA (siRNA) or micro RNA (miRNA).uses the siRNA or miRNA as a template for recognizing complementary mRNA. When it finds a complementary strand, it activates RNase and cleaves the RNA.

endonuclease

an enzyme which cleaves a polynucleotide chain by separating nucleotides other than the two end ones.

Dicer

plays a pivotal role in the initiation of RNA silencing by recognizing double-stranded RNAs (dsRNAs) and cleaving them into small RNAs using its RNase III-like double-stranded RNA-specific nuclease activities.

acetylation

occurs with the transfer of acetyl groups from acetyl coenzyme A (acetyl CoA) to lysine residues by acetyltransferase leading to neutralization of their positive charge.

regulatory sequence

a segment of a nucleic acid molecule which is capable of increasing or decreasing the expression of specific genes within an organism.

untranslated region

a regulatory region of DNA situated at the 5′ end of all protein-coding genes that is transcribed into mRNA but not translated into protein

promotor region

a region of DNA upstream of a gene where relevant proteins (such as RNA polymerase and transcription factors) bind to initiate transcription of that gene

protein coding region

the portion of a gene's DNA or RNA that codes for a protein

histone acetylation

Epigenetic modification that changes chromatin architecture and regulates gene expression by opening or closing the chromatin structure.

x-inactivation

the normal phenomenon in which one of the two X chromosomes in every cell of a female individual is inactivated during embryonic development.

maternal inheritance

maternal attributes that directly affect that trait in her offspring

imprinting

epigenetic phenomenon that causes genes to be expressed or not, depending on whether they are inherited from the female or male parent.

extra nuclear inheritance

the transmission of genes that occur outside the nucleus

somatic mutation

occur in any of the cells of the body except the germ cells (sperm and egg) and therefore are not passed on to children.

epigenetic modifications

modifications to DNA that regulate whether genes are turned on or off. These modifications are attached to DNA and do not change the sequence of DNA building blocks.

attenuation of essential genes

a proposed mechanism of control in some bacterial operons that results in premature termination of transcription

post-transcriptional gene regulation

occurs through the action of RNA binding proteins and processing factors that associate with RNAs from the initiation of transcription to the eventual death of the RNA in the cytoplasm

CpG islands

regions with a high concentration of phosphate-linked cytosine-guanine pairs found in many gene promoters.

epigenomes

made up of chemical compounds and proteins that can attach to DNA and direct such actions as turning genes on or off, controlling the production of proteins in particular cells