CSB329 (Stem Cell Biology) - Week Three Lecture Content

What are the three components are inherited by the progeny cell during cell division that reflect previous cellular states (i.e., producing cell memory)? What happens when these components are inherited asymmetrically in progeny?

1. Organelles (e.g., mitochondria, endoplasmic reticulum)

2. Protein molecules (e.g., transcription factors, membrane-associated proteins)

3. Protein complexes (e.g., modified histones, ribonucleoproteins)

Different cell fates transpire in progeny (e.g., differentiation)

What are the four interactions present in the stem cell niche that regulate stem cell proliferation (i.e., self-renewal) and differentiation?

1. Contact with adjacent cells (i.e., cell-cell interactions)

2. Soluble proteins (e.g., growth factors, cytokines, and chemokines)

3. Insoluble proteins (e.g., extracellular matrix)

4. Mechanical forces (e.g., tension, compression, shear)

Example of the mechanical force tension

Muscle contraction

Examples of the mechanical force compression

Compression of cartilage

Definition of shear force

Movement of fluid perpendicular to the cell surface

Characteristics of the Bilaterian organism body plan (2)

1. Number of discrete germ layers present

2. Development

3. Planes present in body plan

1. Three discrete germ layers presents (i.e., ectoderm, mesoderm, and endoderm)

2. Cephalization occurs during development (i.e., develop of head with sensory tissues)

3. Left and right plane present in body plan

Two Bilaterian organisms

1. Planarian (i.e., flat worm)

2. Drosophila (i.e., fruit fly)

Definition of neoblasts

Adult pluripotent (i.e., clonogenic) stem cells present in Planarians that facilitate tissue homeostasis (e.g., tissue regeneration)

What is the developmental potency of mammalian adult stem cells?

Mammalian adult stem express multipotency, differentiation is restricted to specialized cell types within a germ layer (i.e., tissue of origin)

Location of neoblasts in Planarian species?

Located within mesenchymal tissues surrounding internal structures

How are neoblasts experimentally identified in Planarian species? (i.e., expression of protein)

Expression of smedwi-1, a piwi homolog

Function of smedwi-1 in Planarian species

Regulate tissue homeostasis (i.e., tissue regeneration) by maintaining genome integrity of neoblasts

How are transcripts for smedwi-1 derived in Planarian species? Where are transcripts for smedwi-1 cleaved?

Transcripts for smedwi-1 are derived from mobile elements, and are cleaved inside cytoplasmic granules (i.e., chromatic bodies)

Function of Hoechst

DNA stain that non-specially labels animated cells with an intact nuclei

How were pluripotent identified in Planarian species?

What happens when a transplantation of neoblasts from a rescued, irradiated Planarian to an irradiated Planarian of a distinct species occurs? What experimental procedure is this?

The complementation assay (i.e., development of chimera organism) rescues tissue homeostasis (i.e., tissue regeneration) in distinct Planarian species. Rescued Planarian adopts genome of neoblast donor (i.e., every cell in Planarian is derived from donor neoblast)

Distinct characteristics of transplantation assay

Distinct characteristics of complementation assay