Lecture 18

Study Notes

Cellular Stemness and Signaling Pathways in Development

Hematopoietic stem cells from human bone marrow can divide to produce more HSCs or become different progenitor and differentiated cell types.
The basic transcriptional network regulating the pluripotency of embryonic stem cells involves multiple factors including 5 master TFs: Klf4, Myc, Nanog, Sox2, Oct4.
Induced pluripotent stem cells (iPSCs) can be derived from somatic cells of patients with difficult diseases such as ALS and can give rise to progeny of all 3 germ layers.
Patient-specific iPSCs can be used for gene targeting, gene correction, and direct differentiation into affected neuronal subtypes for medical applications.
Two major cell signaling pathways are controlled by morphogens, which induce different cell fates depending on their concentration at target cells.
Morphogen gradients help establish cell differentiation, body axes, orientation, and patterning of tissues and organs by specifying uniform cells into 3 cell types.
Gradients of Wnt, a morphogen, are essential for the normal regeneration of head and tail by planaria, and its inhibition can result in abnormal regeneration.
Sonic hedgehog (Shh) protein, another morphogen, polarizes developing limbs and its inhibition can lead to abnormal development, as seen in a cycloptic lamb.
The model of Drosophila melanogaster anterior-posterior axis formation provides evidence of the genetic logic of development, involving maternal exis determination genes, gap genes, pair rule genes, and segment polarity genes.
Enhancer modularity and function in the even-skipped (eve) gene of Drosophila melanogaster involves specific promoter regions and competitive interactions between activators and repressors.
Hox gene expression and function in Drosophila melanogaster is crucial for the development of segmental identities in the embryo, as depicted in the expression map of hox genes.
The text discusses the regulation of cell division and differentiation, the transcriptional network regulating pluripotency, the derivation and medical applications of induced pluripotent stem cells, the control and effects of morphogens, and the genetic logic of development in Drosophila melanogaster.

Description

Test your knowledge of cellular stemness, signaling pathways, and developmental biology with this quiz. Explore topics such as hematopoietic stem cell division, transcriptional networks regulating pluripotency, induced pluripotent stem cell derivation, morphogen gradients, and genetic logic of development in Drosophila melanogaster.