MCB 250 Final Exam Hell

Helen Blau scientific work

fused human liver cells to skeletal muscle cells of mice. The hybrid cells began to stain with antibodies specific for human muscle proteins

PitX1 gene

has 4 tissue-specific enhancers, each responds to combo of TF

when different enhancers bind to it it expresses in a particular tissue of the body

Strategies to bring about gene expression in embryos

maternal gene products

intracellular signals

Macho-1 gene

in sea squirt, encodes zinc finger TF that plays role in embryonic tail muscles

how does an egg localize an mRNA to a particular region of its cytoplasm?

some mRNAs have localization signal sequence of their 3’UTR. Sequence can bind RNA to motor protein through adaptor protein intermediate, which in turn uses energy of ATP hydrolysis to move

autophosphorylation

when a protein adds a phosphate group to itself; ex: JAK in JAK/STAT pathway

Achondroplasia

lack of cartilage growth caused by mutated allele for FGFR3. 99% of dominant alleles of this gene

Drosophila fruit fly cycle

The embryo hatches from eggshell as a larva. Three stages of instars, secrete hard casing and becomes a pupa. As instars grow, tissue starts to form, once formed it forms a pupal case.

Syncytial blastoderm

collection of nuclei spread out around edges of embryonic membrane

Zelda

zinc-finger early drosophila activator

What starts the maternal to zygotic transition of the drosophila embryo

Pioneer TF and Zelda

Dorsal closure

the embryo folds in half closing the dorsal side of the embryo

Jani Nusslein-Volhard and Eric Wieschaus

did a genetic screen with goal of identifying all gene that control early development of Drosophila body axes

Discovered: one set of genes controls dorsal-ventral axis, separate set of posterior-anterior axis, molecular analysis of genes revealed that embryo uses different mechanisms to establish axes

Bicoid gene

becomes localized at the future anterior end of the egg

Oskar proteins

cause the pole cells in drosophila embryo to segregate and form germ line tissue

Spatzle

ligand for receptor Toll.

Toll

receptor protein distributed uniformly over the drosophila egg cell membrane

Dorsal TF protein

tethered in cytoplasm by cactus protein, when theres no signal transduction

Consequence of Toll being Activated by its Ligand

causes cactus to be phosphorylated by kinases Pelle and Tube, degrading cactus

how are mutations made available during embryogenesis?

the mutations have to be in the mother

Nurse cells

cells in drosophila egg that produces mRNAs, proteins, lipids, and energy sources that cross the egg membrane to deliver to embryo

oskar gene

localized at posterior end of egg; cells that inherit this gene become the embryo’s germ line

How does oskar protein help form germ line tissue

as the egg develops, the bicoid mRNA is bound to the ‘-’ end of microtubules and the oskar mRNA associates with the ‘+” ends. They relocate to posterior end while bicoid stays in anterior end

lymphocytes

white blood cells that secrete immunoglobulin proteins (antibodies) and aid in adaptive immunity

T cell receptor

synthesized by T lymphocytes; bind foreign antigens and help to destroy cells carrying those antigens

antigen

any molecule that provokes an immune response

ex: proteins associated with parasites, toxins, genetically altered proteins on cancer cells, etc

self-antigens

molecules native to healthy body

Epitope

site of antigen protein that is bound by IgG, generally 5-8 AA

VJ rearrangment

rearrangement of light chain gene of IgG

cas protein functions

1. cleaves backbone of DNA of specific repeat to form pre-crRNA

2. cleaves DS foreign DNA to add to crispr locus as a new spacer

UBE3A

gene associated with angelman syndrome.