Related Experiment Video
Updated: Jun 19, 2026
05:43
Capturing Cytoskeleton-Based Agitation of the Mouse Oocyte Nucleus Across Spatial Scales
Published on: January 12, 2024
INTRANUCLEAR AND CYTOPLASMIC ANNULATE LAMELLAE IN TUNICATE OOCYTES
1Department of Zoology, University of Iowa, Iowa City, Iowa, and the Marine Biological Laboratory, Woods Hole, Massachusetts.
The Journal of Cell Biology
|October 30, 2009
Summary
Electron microscopy reveals how tunicate oocyte nuclear envelopes form annulate lamellae. Inner lamella blebs fuse to create these structures, while outer lamella blebs contribute to endoplasmic reticulum development.
Area of Science:
- Cell Biology
- Developmental Biology
- Electron Microscopy
Background:
- Annulate lamellae are cytoplasmic structures involved in various cellular processes.
- The biogenesis of annulate lamellae, particularly their origin from the nuclear envelope, requires further elucidation.
Purpose of the Study:
- To investigate the origin and formation of annulate lamellae in tunicate oocytes using electron microscopy.
- To characterize the morphological dynamics of the nuclear envelope during oocyte development.
Main Methods:
- Transmission electron microscopy was employed to examine tunicate oocytes at different developmental stages.
- Detailed morphological analysis of the nuclear envelope and associated cytoplasmic structures was performed.
Main Results:
- The inner and outer lamellae of the nuclear envelope exhibit significant blebbing activity.
- Blebs from the inner nuclear envelope fuse to form differentiated annulate lamellae within the nucleoplasm.
- Blebbing of the outer nuclear envelope contributes to the formation of vesicular and granular endoplasmic reticulum in the ooplasm.
Conclusions:
- The nuclear envelope plays a direct role in the biogenesis of annulate lamellae through a blebbing and fusion mechanism.
- The outer nuclear envelope contributes to the synthesis of endoplasmic reticulum during oocyte development.
- Annulate lamellae in tunicate oocytes are likely formed from the nuclear envelope and may be patent structures.
Related Concept Videos
02:10Additional Subnuclear Structures
The eukaryotic nucleus is a double membrane-bound organelle that contains nearly all of the cell’s genetic material in the form of chromosomes. It is rightly called the “brain” of the cell as it shoulders the responsibility of responding to various physiological processes, stress, altered metabolic conditions, and other cellular signals.
The nucleus contains many membrane-less subnuclear organelles or nuclear bodies, such as nucleoli, Cajal bodies, speckles, paraspeckles, etc. These nuclear...
The nucleus contains many membrane-less subnuclear organelles or nuclear bodies, such as nucleoli, Cajal bodies, speckles, paraspeckles, etc. These nuclear...
01:26Ovaries
The ovaries are roughly the size of almonds and measure approximately 2 to 3 centimeters in length. These paired structures are situated within the pelvic region and are anchored by the mesovarium—a peritoneal extension that also connects them to the wider structure of the broad ligament. The support system extends to the suspensory ligament, housing blood and lymphatic vessels. In addition, the ovarian ligament tethers the ovaries to the uterus.
On the ovarian surface, a layer of cuboidal...
On the ovarian surface, a layer of cuboidal...
01:51Lampbrush Chromosomes
In 1882, Flemming observed lampbrush chromosomes (LBC) in salamander eggs. Later in 1892, Rückert observed LBCs in shark egg cells and coined the term "lampbrush chromosomes" because they looked like brushes used to clean kerosene lamps.
LBCs are made up of two pairs of conjugating homologous chromatids. Each chromatid consists of alternatively positioned regions of condensed-inactive chromatin and loosely placed-active side loops, which can be contracted and extended. The loops resemble the...
LBCs are made up of two pairs of conjugating homologous chromatids. Each chromatid consists of alternatively positioned regions of condensed-inactive chromatin and loosely placed-active side loops, which can be contracted and extended. The loops resemble the...
01:13Microscopic Anatomy of Skeletal Muscles
Skeletal muscle cells, also called muscle fibers, are distinctly elongated, multi-nucleated, slender biological units. They are packed with specialized structures designed to facilitate their primary function, which is contraction.
The muscle sarcolemma is a plasma membrane enclosing each muscle cell that conducts electrical signals called action potentials. The sarcolemma extends into the cell to form T-tubules, ensuring the neural impulses are uniformly distributed across the entire muscle...
The muscle sarcolemma is a plasma membrane enclosing each muscle cell that conducts electrical signals called action potentials. The sarcolemma extends into the cell to form T-tubules, ensuring the neural impulses are uniformly distributed across the entire muscle...
01:29Tight Junctions
Tight junctions are molecular seals between cells that prevent the leaking of fluids, ions, and other small solutes across cavities and compartments in multicellular organisms. They are mainly composed of claudin and occludin transmembrane proteins, and other proteins such as tricellulin and JAM (junctional adhesion molecule). All these proteins are 4-pass transmembrane proteins, except JAM, which is a single-pass transmembrane protein belonging to the immunoglobulin superfamily. The...
01:38Intralumenal Vesicles and Multivesicular Bodies
Intraluminal vesicles (ILVs) are small vesicles 50-80 nm in diameter formed during the maturation of early endosomes. A specialized endosome containing numerous ILVs is called a multivesicular body (MVB). ILVs contain internalized molecules such as antigens, nucleic acids, proteins, and metabolites. Some of these molecules are released from the MVBs inside exosomes and are transported to other cells. Other MVBs contain molecules that are retained in the ILVs and are later degraded within the...