Stem Cells in Development & Regeneration

Comprehensive fill-in-the-blank practice flashcards covering stem cell biology, early mammalian development, potency assays, somatic cell reprogramming, epithelial junctions, organoid systems, flow cytometry, and organ-specific stem cell hierarchies.

The molecular signals governing the functional properties of stem cells are collectively defined as __________.

stemness

Stem cells that have the developmental potential to form an entire organism, including both embryonic and extraembryonic tissues, are described as __________.

totipotent

During mammalian pre-implantation development, differential expression of transcription factors segregates early lineages, where __________ specifies the early epiblast and __________ specifies the hypoblast.

NANOG; GATA6

In mouse blastocyst segregation, outer cells express the key transcription factor __________ to maintain trophoblast identity, while inner cell mass cells express OCT4 and SOX2.

CDX2

The most stringent functional assay for pluripotency, in which injected donor stem cells compose the entire resulting fetus because $4n$ host blastocyst cells cannot form embryonic lineages, is __________.

tetraploid complementation

In ESC culture, the "2i" condition suppresses differentiation and maintains ground-state pluripotency by utilizing the MEK inhibitor __________ and the GSK3 inhibitor __________.

PD0325901; CHIR99021

Takahashi and Yamanaka originally selected reprogrammed iPSC colonies from mouse embryonic fibroblasts using drug resistance driven by the promoter of __________, a gene specifically expressed in ESCs.

Fbx15

The four core reprogramming transcription factors originally identified by Yamanaka are OCT4, SOX2, MYC, and __________.

KLF4

Stem cells divide to produce committed __________ cells, which divide rapidly to multiply cell numbers before giving rise to terminally differentiated cells.

transit amplifying

Regeneration involving the growth of completely new, correctly patterned structures from a blastema composed of de-differentiated progenitor cells is termed __________.

epimorphosis

In salamander limb regeneration, cell proliferation within the blastema is dependent upon signals from nerves, specifically the factor __________.

Neuregulin-1 (Nrg1)

Glucose transport across intestinal epithelial cells is restricted to transcellular flux because __________ prevent solutes from diffusing paracellularly between adjacent cells.

tight junctions

Cadherins exhibit __________ binding, meaning they bind identical cadherin molecules on adjacent cells in a calcium-dependent manner, allowing cells expressing different cadherins or expression levels to sort out.

homophilic

In epithelial apico-basal polarity, the __________ scaffold complex localizes to the apical domain near tight junctions and serves as a binding platform for the GTPases Cdc42 and Rac.

Par3-Par6-aPKC

Anchoring junctions called __________ connect intermediate cytokeratin filaments to extracellular laminin within the basal lamina via specialized $\alpha_6\beta_4$ integrins.

hemidesmosomes

Crypt base columnar (CBC) stem cells in the intestinal epithelium specifically express the surface marker receptor __________.

Lgr5

In the small intestinal stem cell niche, __________ cells sit directly adjacent to Lgr5-positive CBC cells and secrete Wnt3a to maintain the stem cell pool.

Paneth

Disruption of stromal BMP signaling along the crypt-villus axis causes the formation of __________ along the sides of the villi.

ectopic crypts

During DNA replication, newly synthesized DNA strands receive maintenance methylation from the enzyme __________, which recognizes hemi-methylated CpG sites.

DNMT1

Polycomb Repressive Complex 1 (PRC1) maintains developmental genes in a silenced state in embryonic stem cells by binding directly to the histone mark __________.

H3K27me3

In melanoma initiation driven by $BRAF^{V600E}$, high oncogenic competence is restricted to early neural crest lineages by the developmental chromatin factor __________.

ATAD2

To prevent the generation of a mosaic embryo when applying CRISPR/Cas9 editing to correct mutations, Cas9 components must be introduced __________.

co-injected with sperm at fertilization

In flow cytometry, the difference between a fluorophore's maximal excitation wavelength and maximal emission wavelength is known as the __________.

Stokes shift

In a flow cytometer, forward scatter (FSC) provides a measurement proportional to cell __________, whereas side scatter (SSC) measures internal cell __________.

size; complexity

During mammalian embryogenesis, definitive haematopoietic stem cells (HSCs) first emerge from the haemogenic endothelium of the __________.

aorta-gonad-mesonephros (AGM)

The five histological stages of mammalian lung development, in chronological order, are embryonic, pseudoglandular, __________, saccular, and alveolar.

canalicular

Dual-positive stem cells situated at the bronchi-alveolar duct junction (BADJ) that express both __________ and __________ can regenerate both airway and alveolar cells.

CC10; SPC

In the Drosophila ovary, BMP signaling from cap cells represses the differentiation factor __________ in germline stem cells to maintain stemness.

BAM (Bag of Marbles)

In the mammary epithelial hierarchy, the transcription factor __________ keeps stem cells quiescent and is required for pubertal ductal growth, while __________ promotes luminal cell differentiation.

Foxp1; Gata-3

In the embryonic development of the kidney, nephron progenitors derive from the __________, whereas the ureteric bud branches from the __________.

posterior intermediate mesoderm (metanephric mesenchyme); anterior intermediate mesoderm (nephric duct)