Related Experiment Video

Updated: Aug 11, 2026

Protocols for Microapplicator-assisted Infection of Lepidopteran Larvae with Baculovirus
10:40

Protocols for Microapplicator-assisted Infection of Lepidopteran Larvae with Baculovirus

Published on: August 23, 2008

Control of programmed cell death by the baculovirus genes p35 and iap

R J Clem1, L K Miller

  • 1Department of Genetics, University of Georgia, Athens 30602-2603.

Molecular and Cellular Biology
|August 1, 1994
PubMed

Insights

Apoptosis in insect cells is triggered by the cessation of RNA synthesis. Baculovirus inhibitor of apoptosis (iap) genes and p35 protein block this process, acting directly on cellular pathways.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Virology

Background:

  • Insect cell lines like SF-21 are susceptible to apoptosis.
  • Baculovirus infection and actinomycin D treatment can induce apoptosis.
  • Apoptosis is a key cellular process regulated by specific genes.

Purpose of the Study:

  • To investigate the molecular basis of apoptosis induction in SF-21 cells.
  • To determine the role of baculovirus p35 and inhibitor of apoptosis (iap) genes in blocking apoptosis.
  • To elucidate the mechanism by which these genes confer anti-apoptotic function.

Main Methods:

  • Treatment of SF-21 cells with actinomycin D.
  • Infection of SF-21 cells with baculovirus mutants lacking p35 or iap genes.
  • Expression of viral and mammalian apoptosis-regulating genes.
  • Analysis of apoptosis induction and inhibition.

Main Results:

  • Cessation of RNA synthesis is identified as the common trigger for apoptosis induced by both stimuli.
  • Expression of baculovirus p35 or functional iap homologs effectively blocks apoptosis.
  • The anti-apoptotic function of iap genes depends on specific amino acids within the C3HC4 finger and baculovirus iap repeat.
  • Mammalian apoptosis inhibitors (bcl-2, E1B-19K) do not prevent actinomycin D-induced apoptosis in SF-21 cells.

Conclusions:

  • Apoptosis induction in SF-21 cells by actinomycin D or specific baculovirus mutants is linked to RNA synthesis inhibition.
  • Baculovirus p35 and iap genes directly target the cellular apoptotic pathway to prevent cell death.
  • The structural domains of iap proteins are critical for their anti-apoptotic activity, suggesting a conserved mechanism.

More Related Videos

Transient Expression of Foreign Genes in Insect Cells (sf9) for Protein Functional Assay11:12

Transient Expression of Foreign Genes in Insect Cells (sf9) for Protein Functional Assay

Published on: February 22, 2018

Modifying Baculovirus Expression Vectors to Produce Secreted Plant Proteins in Insect Cells09:14

Modifying Baculovirus Expression Vectors to Produce Secreted Plant Proteins in Insect Cells

Published on: August 20, 2018

Related Concept Videos

CRISPR and crRNAs02:53

CRISPR and crRNAs

Bacteria and archaea are susceptible to viral infections just like eukaryotes; therefore, they have developed a unique adaptive immune system to protect themselves. Clustered regularly interspaced short palindromic repeats and CRISPR-associated proteins (CRISPR-Cas) are present in more than 45% of known bacteria and 90% of known archaea.
The CRISPR-Cas system stores a copy of foreign DNA in the host genome and uses it to identify the foreign DNA upon reinfection. CRISPR-Cas has three different...
Caspases01:24

Caspases

Caspase, a family of cysteine proteases, serve as effectors in apoptosis. The ced3 gene in C.elegans was first identified to be involved in apoptosis. This gene encodes the ced-3 caspase that is similar to the interleukin-1-beta converting enzyme or ICE in mammals. In addition to apoptosis, caspases also function in the inflammatory response. Inflammatory caspases are essential in activating pro-inflammatory cytokines that recruit immune cells and block the replication of pathogens inside cells.
The Extrinsic Apoptotic Pathway01:17

The Extrinsic Apoptotic Pathway

The extrinsic apoptotic pathway is initiated when extracellular death-inducing signals, such as specific cytokines, activate the death receptors expressed on the cell surface. The immune cells involved in this pathway are natural killer cells (NK cells) and cytotoxic T-lymphocytes. NK cells are critical in innate immune response, while cytotoxic T-lymphocytes are associated with adaptive immune response. These cells recognize specific receptors expressed on the altered cells and activate...
The Intrinsic Apoptotic Pathway01:31

The Intrinsic Apoptotic Pathway

Internal cellular stress, such as cellular injury or hypoxia, triggers intrinsic apoptosis. The B-cell lymphoma 2 (Bcl-2) family of proteins are the primary regulators of the intrinsic apoptotic pathway. For example, during DNA damage, checkpoint proteins, such as Ataxia Telangiectasia Mutated (ATM protein) and Checkpoints Factor-2 (Chk2) proteins, are activated. These proteins phosphorylate p53 which further activates pro-apoptotic proteins, such as Bax, Bak, PUMA, and Noxa, and inhibits...
Production of Biopesticides01:18

Production of Biopesticides

Biopesticides offer a sustainable alternative to chemical pesticides, utilizing microbial agents to control agricultural pests. Bacillus thuringiensis (Bt) is a widely employed bacterium known for its potent insecticidal activity. Bt biopesticides are favored for their specificity to insect pests, minimal environmental impact, and natural degradability.Mechanism of Bt Toxin Action Bt produces insecticidal crystal (Cry) proteins during its sporulation phase. These proteins form parasporal...
Cellular Injury V: Apoptosis and Autophagy01:22

Cellular Injury V: Apoptosis and Autophagy

Cells respond to damage and stress through highly coordinated processes that decide whether they survive or undergo controlled self-destruction. Two major pathways involved in this regulation are apoptosis, a type of programmed cell death, and autophagy, a survival mechanism that helps cells adapt to adverse conditions.ApoptosisApoptosis removes aged or injured cells to maintain tissue balance. During this process, the cell shrinks, chromatin condenses and fragments, and membrane-bound...