Gene Expression and RNA Processing in Eukaryotes

mRNA reading direction

Ribosome reads mRNA 5' to 3' direction.

Protein synthesis direction

Proteins are synthesized N-terminus to C-terminus.

Splicing in eukaryotes

Splicing occurs in the nucleus, not cytoplasm.

Spliceosome components

Spliceosome consists of snRNPs and snRNAs.

Introns in primary transcript

Introns are present in eukaryotic primary transcript.

Amino acid attachment to tRNA

Amino acyl tRNA synthetases attach amino acids to tRNA.

Proteasome function

Proteasome degrades proteins tagged by ubiquitin.

Misfolded proteins and proteasome

Misfolded proteins are not refolded by proteasome.

tRNA anticodon

tRNA with anticodon 3'-GAA-5' carries leucine (Leu).

Non-complementary RNA sequence

Poly A tail is not encoded by DNA.

5' cap nucleotide

5' cap contains a methylated guanosine nucleotide.

Gene transcription on chromosome

Adjacent genes can be transcribed at different rates.

RNA folding

RNA can fold into various shapes due to uracil.

Heat shock proteins

Chaperones assist in protein folding after heat shock.

Lariat structure

Lariat structure is an intermediate in splicing.

TATA box function

TATA box is a promoter sequence in transcription.

5' UTR role

5' UTR is part of mRNA before the coding region.

PolyA tail function

PolyA tail stabilizes mRNA and aids in translation.

Shine-Dalgarno sequence

Shine-Dalgarno is involved in prokaryotic translation initiation.

Initiation factors

Initiation factors assist in starting protein synthesis.

Elongation factors

Elongation factors facilitate the elongation of polypeptides.

Ubiquitin role

Ubiquitin marks proteins for degradation by proteasome.

RNA bases

Cannot form hydrogen bonds with each other.

RNA nucleotides

Use different chemical linkages than DNA.

Single-stranded RNA

RNA exists as a single strand.

Transcription example

5'-AUAGGCAUUCGAUCCGGAUAGCAU-3' from DNA.

Ubiquitin

Small protein marking proteins for proteasome delivery.

Proteasome function

Degrades misfolded proteins to prevent cytoplasmic accumulation.

Proteases

Enzymes located in the proteasome's central cylinder.

Protein stoppers

Use ATP hydrolysis energy to move proteins inside.

Neuron function

Receives and responds to electrical signals.

White blood cell function

Defends the body against infections.

Differential gene expression

Results in distinct cell characteristics in multicellular organisms.

Transcription regulation

Mainly involves transcription of genes by RNA polymerase II.

Operons

Clusters of genes transcribed as a single mRNA.

Eukaryotic transcription regulators

Effect transcription by looping DNA to the promoter.

Combinatorial control

Uses different combinations of regulators for gene expression.

Gene activators

Proteins that enhance transcription of specific genes.

Differentiated cells

Cells that no longer need to transcribe all genes.

Housekeeping genes

Genes required for basic cellular functions.

TATA box

DNA sequence that binds transcription factors in eukaryotes.

RNA polymerase assembly

Process where RNA polymerase binds to the promoter.

Misfolded proteins

Proteins that fail to achieve proper structure.

Gene expression

Process by which information from a gene is used.

Transcriptional Regulators

Groups that control gene expression collaboratively.

MicroRNAs

Small RNA molecules affecting gene translation.

Eve Gene

Gene with modular regulatory regions for expression.

Regulatory Elements

DNA segments that drive gene expression in stripes.

Transcription

Process of synthesizing RNA from DNA template.

Nucleotide Polymerization

Occurs only in the 5'-to-3' direction.

Total Nucleic Acids

Extracted from yeast cells for analysis.

mRNA

Most abundant nucleic acid in the analysis.

MicroRNA Function

Control gene expression by base-pairing with mRNAs.

tRNA

RNA that translates genetic code into proteins.

Ubiquitin

Marks proteins for degradation in the cell.

Translation

Process requiring mRNA and tRNA for protein synthesis.

Operon Model

Explains coordinated gene expression in bacteria.

RNA Processing

Involves removal of introns from mRNA.

Catalytic Activity

Intrinsic ability of some RNAs to degrade other RNAs.

Transcriptional Activators

Proteins that enhance transcription of specific genes.

LacZ Gene

E. coli gene expressed in a single stripe.

RNA Polymerase

Enzyme that synthesizes RNA from DNA template.

Gene Expression Specialization

Process by which precursor cells differentiate into specialized types.

RNA Primer

Short RNA segment used in DNA replication.

Promoter

Regulatory sequence for RNA polymerase binding.

Base Pairing

Complementary binding of RNA to DNA or mRNA.