Biog 1350 Prelim 3 Terms

special type of mitotic cell division without cell growth.
S phase and M phase (M follows S), no G1 or G2.

phase in fertilization during which newly formed embryo undergoes many rounds of cell division without growth

a cleaving cell.

the embryo at the end of cleavage.

blastodisc in birds and fish, blastocyst in mice and humans, blastoderm in insects.

dramatic reorganization of the embryo.

1. Some cells leave the monolayer and crawl inside the embryo.
2. Cells on the bottom side of cell invaginate.
3. Mesoderm cells migrate.
4. Some cells on ventral side of mesoderm attach to invagination and pull it up towards the top of the cell.
5. The mouth forms and the cells begin to further specialize (formation of future skeleton, gut tube, future anus, and mouth).

Forms 3 germ layers: ectoderm, mesoderm, endoderm.

consists of the mesoderm and endoderm.

gametes.

sperm and eggs.

one of the germ layers of the early embryo

outer layer of the gastrula

Eventually becomes skins, lenses of eyes, peripheral nervous system, external structure.

one of the germ layers of the early embryo

middle layer of the gastrula

part of the soma.

eventually becomes notochord, bones, part of kidneys, blood, muscles.

one of the grrm layers formed during animal embryogenesis

inner layer of the gastrula

part of the soma.

eventually becomes digestive organs, lungs, internal structure.

formation of the nervous system

only happens in vertebrates (invertebrates have a different process):

1. shaping of neural plate
2. folding begins to form notochord
3. elevation of hillocks around notochord
4. convergence as hillocks combine
5. once completely combined, it is called the neural crest
6. epidermis forms over neural crest
   

formation of specific organs such as lung, stomach, eye, or limbs

All cells have the same DNA but different genes are expressed to give cells their unique character.
Series of events leading to production of the final product of a gene.
Cells "remember" their identity.

Two components:
transcriptional and posttranscriptional controls
developmental events

process by which embryos determine which cells give rise to head and tail (anterior/posterior axis), back and belly (dorsal/ventral axis) and left and right sides (left/right axis).

many different events that lead to the precise shapes and sizes of the parts of the body

refers to the organization of cells into tissues and organs, occurs during gastrulation, neurulation and organogenesis

many different events that lead to the precise placement of body parts with respect to one another

can refer to axis formation, the proper placement and organization of a limb or other organ or the reproducible patterns of feathers on a bird or spots on a butterfly wing

the process by which a gene makes its effect on an cell or an organism by directing the synthesis of a protein or an RNA molecule with a characteristic activity

describes what a particular cell at a given stage of development will normally give rise to

fluid-filled central cavity of a blastocyst

crucial to organogenesis and gastrulation

formed by cleavage and cell migration

tracking each individual cell through all divisions, transformations, and migrations in the embryo to determine a map describing the fate of each cell


requires that division patterns are reproducible

the process of marking single or multiple cells at a particular stage in development and later observing the location and identity of the marked cells

commitment to a particular specialized path of development


reflects a change in the internal character of the cell

precedes the much more readily detected process of cell differentiation

the process by which a cell undergoes a change to an overtly specialized cell type


happens after determination

determination resulting from cell-intrinsic properties (cytoplasmic determinant) which can arise from asymmetric cell division

cytoplasmic molecules (proteins, mRNA, regulatory RNA, etc) that influence cell fate

cell division that produces two daughter cells taht differ, for example in size or in the presence or absence of some cytoplasmic constituent

determination that relies on cues and interactions between cells or from morphogen gradients

a change in the developmental fate of one tissue caused by an interaction with another tissue

progressive series of local inductions that produce successive levels of detail, as in the development of an organ

gradients of signal molecules (called morphogens) that can impose a pattern on a field of cells by causing cells in different places to adopt different fates.

a metaphor for cell determination


increasing irreversibility of cell specialization is visualized as a marble rolling down a hill with multiple ridges

a signal protein whose graduated distribution is important in specifiying anterior vs. posterior developing limb buds as well as other various roles in patterning during development

describes the way in which groups of proteins work together in combination to control the expression of single gene

about 50 nucleotides upstream of the start site of transcription that contains sequences recognized and bound by RNA polymerase

DNA sequence to which a transcription regulator binds to determine when, where, and in what quantities a gene is to be transcribed into RNA


segment of DNA where regulatory proteins such as transcription factors bind preferentially

protein that binds specifically to a regulatory DNA sequence and is involved in controlling whether a gene is switched on or off

a protein that binds to a specific regulatory region of DNA to prevent transcription of an adjacent gene

a protein that binds to a specific regulatory region of DNA to permit transcription of an adjacent gene

a complex of DNA with proteins found in eukaryotic cells

proteins that assemble on the promoters of many eukaryotic genes near the start site of transcription and load the RNA polymerase in the correct position

DNA sequence typically 25 nucleotides upstream from transcription start sites of genes that is rich in A and T nucleotides and binds general transcription factors as a prerequisite for RNA polymerase loading and positioning

regulatory DNA sequence to which transcription regulators bind, influencing the rate of transcription of a structural gene that can by many thousands of base pairs away

forms a core composed of 2 copies of each of four distinct histone proteins, which DNA is wrappeed around to form chromatin

histone H1

required for the assembly of the 30 nm fiber

protein machines that use the energy of ATP hydrolysis to change the position of the DNA wrapped around nucleosomes

each histone's tail can be modified by adding a chemical group like a methyl, acetyl, or phosphate group.


pattern of modification can dictate how a stretch of chromatin is treated by the cell

inheritance that is superimposed on the information inherited in the DNA sequence itself.


often, information in the form of a particular type of chromatin structure (e.g. a certain pattern of histone modification or DNA methylation)

the enzymatic addition of methyl groups to cytosine bases in DNA


generally turns off genes by attracting proteins that block gene expression

the fertilized egg or one-cell embryo

one of the cells at about the 16-24 cell stage of C. elegans embryonic development


the founder cell of the entire germ line

germ line: the only type of cells that can pass the DNA to the next generation through the ability to generate the gametes (sperm and egg)

soma line: all of the cells in the body that are NOT the germ line

complex aggregates called ribonucleoprotein particles composed of RNA and proteins.
cytoplasmic proteins that were localized prior to cell division and were partitioned exclusively to the germ line, finally residing in P4 and getting passed on to all of its progeny.
PGL-1 and PGL-3 have allowed tests on its function.
Segregation to germ line not required for germ line fate determination.
maintain cell divisions in germ line. manage stresses to germ line cells.

a component of P granules protein


necessary for germ cell proliferation

a component of P granules protein


necessary for germ cell proliferation

a gene in C. elegans embryonic development

encodes a regulatory subunit of a phosphatase

mutants result in a failure of P granules to become localized to the germ line, but germ cells are specified in spite of that

a transcriptional regulator that acts as a general repressor of transcription

a cytoplasmic protein that appears to contribute to germ line fate determination in C. elegans embryonic development

mutations in encoding gene resulted in phenotype of embryonic lethality in which the arrested embryos exhibited pharynx and intestine in excess. embryos also lacked germ line cells.

required for germ-line development

blastomere

daughter of PIE-1

sister plastomere to P2

daughter of PIE-1

partitioning defective

in C. elegans embryonic development, mutations in the genes result in phenotypes that reflect defects in localizing factors that regulate differences between the anterior and posterior cells during the first two cleavages

phenotypes include equal first cleavage and failure of P granules to localize properly

in C. elegans embryonic development, loss of mex-5 results in an absence of germ line cells and an excess of muscle

found to be localized to the anterior of fertilized egg

tissue with special ability to organize tissue surrounding it to form a second embryonic axis in the host

functionality of an organizer

pgimented pole of Xenopus egg

unpigmented, yolk-rich half of Xenopus egg

a form of metabolic control in which the end product of a chain of enzymatic activities reduces the expression levels for these enzymes

the basic unit of chromatin composed of a strand of DNA wrapped 1.7 times (147 nucleotide base pairs) around an octomeric histone core

several distinct classes of enzyme can modify histones at multiple sites.


enzymes have been identified for acetylation, methylation, demethylation, phosphorylation, and many other forms of modification