Glossary
Homeodomain transcription factor
A homeobox is a DNA sequence found within genes that are involved in morphogenesis and development. It encodes a protein domain known as homeodomain, which when expressed (eg. as a protein) can bind DNA. The transcription factors bind to the specific DNA sequences and thereby control the...
Hypoplasia
Underdevelopment or incomplete development of a tissue or organ.
In-vitro
The state of being in an artificial environment outside the living organism.
Lamina
Another word for "layer". The different lamina are the different layers of, for example, the cerebellar or the cerebral cortex.
Lateral inhibition
The capacity of an excited neuron to reduce the activity of its neighbors.
Microcephaly
Abnormally decreased size of the head.
Mitogens
A chemical substance that encourages a cell to commence cell division, triggering mitosis. A mitogen is usually some form of a protein.
Mitogens trigger signal transduction pathways in which mitogen-activated protein kinase is involved, leading to mitosis.
Organizer
An area of cells capable of inducing changes within the cells adjacent to it.
Paired box genes
Also known as Pax genes. These are a family of tissue specific transcription factors contaning a paired domain and usually a partial or complete homeodomain. There are four well defined groups of Pax genes within the mammalian family.
Post-mitotic cells
Cells in G0 phase are in a non-diving phase. Thus, they have reached maturity and are terminally differentiated. They are now known as post-mitotic cells and continue to perform their main functions throughout the rest of the organism’s life.
Precursor cell
A type of partially differentiated, usually unipotent cell that has lost most or all of the stem cell multipotency. They are usually capable of differentiating into one or two closely related final forms.
Preplate
Neuronal precursor cells proliferate in the ventricular zone of the developing neocortex. The first postmitotic cells to migrate form the preplate which are destined to become Cajal-Retzius cells and subplate neurons. These cells do so by somal translocation.
Progenitor cells
Cells that have the capacity to differentiate into a specific type of cell, but are already far more committed. They can only divide a limited number of times.
