ex22 Flashcards
Robertsonian Translocation
A chromosomal rearrangement involving fusion of two acrocentric chromosomes (13, 14, 15, 21, 22) with loss of short arm material, typically resulting in phenotypically normal individuals.
Histone Acetylation
A modification where histone acetyltransferases (HATs) acetylate lysine residues on histone tails, reducing positive charge and loosening DNA-histone interactions to promote transcription.
Autosomal Dominant Inheritance
A genetic inheritance pattern where one mutated copy of a gene is sufficient to cause disease, affecting both males and females equally.
LDL-Receptor Mutation
A mutation in the LDL-receptor gene associated with familial hypercholesterolemia, where one inactivating mutation is sufficient to impair cholesterol clearance.
Aptamers
Short nucleic acid sequences that bind specific ligands with high affinity through unique 3D structures, used in therapeutics and diagnostics.
TET Enzymes
Ten-Eleven Translocase enzymes that catalyze the oxidation of 5-methylcytosine to 5-hydroxymethylcytosine, facilitating active DNA demethylation.
BLAST Tool
A bioinformatics tool used for sequence alignment to identify homologous regions, predict protein functions, and model 3D structures.
Scoring Matrices
Matrices used in sequence alignment to score amino acid substitutions based on evolutionary conservation, with higher scores representing greater similarity.
Totipotent Cells
Stem cells with the ability to differentiate into all cell types, including embryonic and extraembryonic tissues, such as those formed by zygotes.
Beta-Cell Mass Estimation
Measured by plasma C-peptide levels, which reflect endogenous insulin production and are unaffected by exogenous insulin therapy.
ncRNAs in Disease
Non-coding RNAs (e.g., miRNAs and lncRNAs) that regulate gene expression and harbor many disease-associated genetic variants in non-coding regions.
Seed Region of miRNA
A critical sequence in the mature microRNA that binds target mRNAs
TET Enzyme Reaction
Catalyzes the oxidation of 5-methylcytosine to 5-hydroxymethylcytosine, critical for active DNA demethylation and epigenetic regulation.
Protein Sequence Alignment
Used to infer homology, predict functional domains, and create 3D models of protein structures for therapeutic and research purposes.
CpG Islands
Regions with high CpG density, usually unmethylated and associated with promoters of actively transcribed genes.
Cyclin-Dependent Kinase Inhibitors
Proteins like p21 and p27 that regulate the cell cycle, often downregulated in cancers to allow uncontrolled proliferation.
Histone N-terminal Tails
Regions subject to post-translational modifications such as acetylation, methylation, and phosphorylation, regulating chromatin structure and gene expression.
Hypercholesterolemia
A condition often caused by mutations in the LDL-receptor gene, leading to impaired clearance of LDL cholesterol and elevated plasma cholesterol levels.
C-peptide
A biomarker for beta-cell function, providing an accurate measure of endogenous insulin production in patients with diabetes.
Epigenetic Modifications
Chemical changes to DNA or histones, such as methylation or acetylation, that regulate gene expression without altering the DNA sequence.
DNA Demethylation
The process of removing methyl groups from 5-methylcytosine, often mediated by TET enzymes, allowing genes to be reactivated.
Unbalanced Robertsonian Translocation
A chromosomal rearrangement where genetic material is lost, typically involving acrocentric chromosomes, potentially leading to phenotypic abnormalities.
Histone Acetyltransferases
Enzymes that acetylate lysine residues on histones, reducing DNA-histone affinity and promoting gene expression.
Non-Coding RNAs
Functional RNA molecules, such as miRNAs and lncRNAs, that regulate gene expression without coding for proteins.
CpG Methylation
A common epigenetic modification where cytosines in CpG dinucleotides are methylated, often silencing gene expression.
BLAST Alignment Tool
Bioinformatics software for comparing nucleotide or protein sequences to identify homologs or functional similarities.
Seed Region of miRNA
A critical region in microRNAs that binds target mRNAs, with mutations here having significant regulatory impacts.
Cyclins
Proteins that regulate cell cycle progression, often overexpressed in cancers to drive uncontrolled cell division.
Histone Modifications
Post-translational changes, such as acetylation and methylation, that influence chromatin accessibility and transcription.
Totipotency
The ability of a single cell, like a zygote, to differentiate into all cell types, including both embryonic and extraembryonic tissues.
Protein Scoring Matrices
Matrices like PAM and BLOSUM used in sequence alignment to score the likelihood of amino acid substitutions based on evolutionary conservation.
Aptamer Function
Bind specific targets like proteins or small molecules with high specificity, used in diagnostics and therapeutics.
Cytoplasmic lncRNAs
Non-coding RNAs that often act as sponges for miRNAs, regulating their activity and downstream effects.
Autosomal Inheritance
A pattern of inheritance where mutations on non-sex chromosomes (autosomes) can affect both males and females equally.
Beta-Cell Function
Assessed by measuring C-peptide levels, reflecting endogenous insulin production and pancreatic activity.
Epigenetic Regulation
Control of gene expression through mechanisms like DNA methylation and histone modification, without altering the DNA sequence.
DNA Repair Mechanisms
Systems like base excision repair and nucleotide excision repair that correct DNA damage to maintain genomic stability.
miRNA Promoter SNPs
Mutations in the promoter regions of microRNAs can alter their expression levels and affect downstream gene regulation.
PCNA Function
A sliding clamp that coordinates DNA polymerase and other replication machinery to ensure efficient DNA synthesis.
Apoptosis Regulation
Programmed cell death regulated by caspases and factors like BCL-2, critical for development and immune responses.
Hypercholesterolemia Genetics
Often caused by mutations in LDL-receptor genes, leading to impaired cholesterol uptake and elevated blood lipid levels.
Histone Methylation
A modification that can activate or repress transcription, depending on the site and context of methylation on histone tails.
Immune Checkpoints
Molecules like PD-1 and CTLA-4 that regulate immune responses, often exploited by cancers to evade immune detection.
Cytokine Storm
A hyperactive immune response characterized by excessive cytokine release, sometimes triggered by immune therapies.
TET Enzyme Oxidation
Converts 5-methylcytosine to 5-hydroxymethylcytosine, initiating DNA demethylation and epigenetic reprogramming.
RNA Interference
A biological process where small RNAs, like siRNAs or miRNAs, silence gene expression by degrading target mRNAs or blocking translation.
DNA Methylation in Somatic Cells
Approximately 60-80% of CpG sites are methylated, primarily in repetitive and non-coding regions, maintaining genomic stability.
Cyclin-Dependent Kinases (CDKs)
Enzymes that regulate the cell cycle, often overactive in cancer due to dysregulated cyclins or loss of CDK inhibitors.
C-peptide Levels
A reliable indicator of endogenous insulin production, used to estimate beta-cell mass in diabetes patients.
ncRNA Variants
Many disease-associated genetic variants are found in non-coding regions, affecting the function of miRNAs and lncRNAs.
Epigenetic Plasticity
The ability of cells to modify their gene expression through epigenetic changes like DNA methylation or histone acetylation in response to environmental stimuli.
MicroRNA Seed Mutations
Mutations in the seed region of miRNAs can disrupt their ability to bind target mRNAs, leading to dysregulated gene expression.
CpG Island Methylation
Regions of high CpG density in promoters, typically unmethylated in active genes but hypermethylated in silenced genes.
Histone Deacetylases (HDACs)
Enzymes that remove acetyl groups from histones, increasing chromatin compaction and repressing gene transcription.
Apoptotic Caspases
Proteases activated during apoptosis through dimerization and auto-proteolytic cleavage, leading to cell death.
Germline Mutations
Inherited mutations present in all cells, often causing hereditary diseases like familial hypercholesterolemia.
Stem Cell Differentiation
The process where stem cells specialize into specific cell types, such as neurons or muscle cells, through signaling pathways and transcription factors.
Topoisomerase Inhibitors
Drugs like irinotecan and doxorubicin that target topoisomerases to prevent DNA unwinding, causing DNA damage and apoptosis in cancer cells.
G1 Phase
The longest phase of the cell cycle, where cells grow and prepare for DNA replication, typically containing the highest number of cells in a population.
Ischemic Stroke
A stroke caused by a blood clot blocking an artery, treated with thrombolysis (e.g., tPA) or mechanical thrombectomy to restore blood flow.
Hemorrhagic Stroke
A stroke caused by bleeding in the brain, treated by controlling blood pressure and surgical interventions like aneurysm clipping.
Circle of Willis
An arterial network at the base of the brain that ensures collateral blood flow, protecting against ischemic injury during vessel blockages.
DNA Repair
Mechanisms such as base excision repair and nucleotide excision repair that maintain genome integrity by correcting DNA lesions.
Endogenous DNA Damage
Most DNA damage arises from internal sources like reactive oxygen species (ROS) and replication errors, rather than external factors.
Gene Regulation by lncRNAs
Long non-coding RNAs modulate gene expression by interacting with chromatin, transcription factors, or sponging miRNAs.
DPP4 Inhibitors
Drugs that prolong the activity of GLP-1, enhancing insulin secretion and improving glycemic control in type 2 diabetes.
Roux-en-Y Gastric Bypass
A surgical procedure for weight loss that also induces type 2 diabetes remission by altering gut hormones like GLP-1 and PYY.
Histone Methylation Marks
Methylation at specific histone residues can activate (e.g., H3K4me3) or repress (e.g., H3K27me3) transcription, depending on the context.
miRNA Function
MicroRNAs regulate gene expression post-transcriptionally by binding to complementary mRNA sequences, leading to degradation or translational inhibition.
Aptamer Technology
Synthetic nucleic acids used as high-affinity ligands for proteins, enabling applications in drug development, diagnostics, and molecular research.
