Trans-splicing is rare in multicellular eukaryotes, it occurs as the primary mechanism to process precursor RNA into mature, translatable mRNAs in some organisms, such as trypanosomes and nematodes.

TLS Online TPP Program

#Id: 7898

#Unit 2. Cellular Organization

TLS Online TPP Program

#Id: 7899

#Unit 2. Cellular Organization

Only 22 tRNAs are required for mitochondrial protein synthesis. The normal codon–anticodon pairing rules are relaxed in mitochondria, so that many tRNA molecules recognize any one of the four nucleotides in the third (wobble) position, allowing four codons to be recognized by a single tRNA.

TLS Online TPP Program

#Id: 7900

#Unit 2. Cellular Organization

Leber’s hereditary optic neuropathy

caused by a missense mutation in the mtDNA gene

encoding subunit 4 of the NADH-CoQ reductase

TLS Online TPP Program

#Id: 7901

#Unit 2. Cellular Organization

Deletions in mtDNA cause another set of diseases:

Chronic progressive external ophthalmoplegia

Kearns–Sayre syndrome

TLS Online TPP Program

#Id: 7902

#Unit 2. Cellular Organization

Single mutation in the TΨCG loop of the mitochondrial lysine tRNA

“Ragged-red” muscle fibers & uncontrolled jerky movements

TLS Online TPP Program

#Id: 7903

#Unit 2. Cellular Organization

Mitochondrial fusion and fission are mediated by a set of GTPase enzymes:

Mitochondrial fusion -MFN1/2 & OPA1

Mitochondrial fission- DRP1