How do cytoplasmic determinants affect gene expression?
The main role of cytoplasmic determinants is the regulation of gene expression. Due to the uneven distribution of cytoplasmic determinants within the cytoplasm, the daughter cells inherit different amounts of them during cell division. Therefore, the gene expression in daughter cells may also differ from each other.
What is meant by cytoplasmic determinants?
For our purposes, cytoplasmic determinants are defined as entities localized in specific cytoplasmic regions of the egg or embryonic cell that bias the cells containing them to assume particular properties or fates during embryogenesis.
How do cytoplasmic determinants and induction work?
Unlike the segregation of cytoplasmic determinants, induction is an extrinsic process that depends on the position of a cell in the embryo. Two identical cells can follow different fates if one is exposed to an external signal (often produced by a different cell) while the other is not.
What are cytoplasmic determinants made of?
When the embryo has become a solid mass of blastomeres (called a morula), it generally consists of two or more differently committed cell populations—a result of the blastomeres having incorporated different cytoplasmic determinants. Cytoplasmic determinants may consist of mRNA or protein in a…
What are examples of cytoplasmic determinants?
The factors responsible for this early mapping out, within zygotes, of subsequent cell fate determination are termed cytoplasmic determinants. They consist, for example, of stored mRNAs as well as proteins and various regulatory factors that found within the cytoplasm of the egg cell.
Why is cytoplasmic determinants important?
Unsourced material may be challenged and removed. Cytoplasmic determinants are special molecules which play a very important role during oocyte maturation, in the female’s ovary. Thus, all the organs of the future embryo are distributed and operating well thanks to the right position of the cytoplasmic determinants.
Where are cytoplasmic determinants found?
Cytoplasmic determinants are also found in some post-embryonic cells, where they produce cytoplasmic asymmetry (q.v.). In dividing cells, this leads to asymmetric cell division in which each of the daughter cells differentiates into a different cell type.
Are Morphogens cytoplasmic determinants?
Morphogens can consist of cytoplasmic proteins, such as transcription factors that form a gradient by diffusion within a single cell or syncytium, or secreted signaling molecules that travel from cell to cell.
Are cytoplasmic determinants proteins?
In the egg, such determinants are usually maternal mRNAs and proteins. Cytoplasmic determinants are also found in some post-embryonic cells, where they produce cytoplasmic asymmetry (q.v.).
What are morphogenetic determinants?
In these embryos, morphogenetic determinants (certain proteins or messenger RNAs) are placed in different regions of the egg cytoplasm and are apportioned to the different cells as the embryo divides. These morphogenetic determinants specify the cell type.
What are nuclear determinants?
Inheritance is strictly through the germ cell lineage. The figure below illustrates another idea proposed by Weismann, that nuclear “determinants” are unevenly segregated to different cells during the cleavage stage of development and specific different cell fates. All animals are made up of communities of cells.
Where are cytoplasmic determinants found in a cell?
Cytoplasmic determinants are also found in some post-embryonic cells, where they produce cytoplasmic asymmetry (q.v.). In dividing cells, this leads to asymmetric cell division in which each of the daughter cells differentiates into a different cell type. Also called localized cytoplasmic determinants or morphogenetic determinants.
How are cytoplasmic determinants used to change gene expression?
Cytoplasmic determinants within the cell help this, but cells also produce chemicals which they secrete and send to other cells Some of these chemicals are called signaling molecules, molecules that instruct another cell to change its gene expression.
How are cytoplasmic determinants related to signal induction?
Cytoplasmic Determinants. This means that each nucleus is exposed to different molecules, and as those molecules interact with the genetic material inside the nucleus, they start activating different genes. So, from the first divisions of the zygote into new cells, these cells are focused on certain genes over others.
How does the microtrabecular lattice influence cell differentiation?
The microtrabecular lattice may influence differentiation of cell types. Cell differentiation may be brought about by the differential localization of various determinants in embryos ( Wilson, 1925; Davison, 1976). These cytoplasmic determinants appear to be, in part, maternal messenger RNA molecules.