Lecture 6- sperm cell differentiation:
- Ex: physiological differentiation of RBCs- for example: how much oxygen it
bound to the hemoglobin.
- Gene activity is central to cell differentiation.
- Sertoli cells take up extra cytoplasm from the spermatocyte.
- Tubulin and dynein are microtubule proteins.
- Acrosome includes acrosin which is a digestive enzyme.
- Nucleus: protamines needed
- Sperm egg recognition happens on two levels: 1. Sperm has a basic idea about
where the egg is so it knows where to go. 2. When the sperm and egg come into
contact, the sperm recognizes the egg as the target object.
- Nucleus elongation makes the sperm more streamlined.
- Histones are bigger than protamines. The goal is to make sperm as compact as
possible so protamines are a better choice for packaging DNA in sperm.
- Nucleosomes= histones with DNA wrapped around. Beads on a string analogy.
- Once fertilization occurs, DNA has to be unwound so that gene expression can
happen in the developing zygote. Protaminehistone shift occurs. The histones
that are used in the transition must come from the oocyte.
- Chromatin remodelling factors also come from the oocyte
- The ma