Does transcription occur in the mitochondria?

In bacteria, ribosomes are directly associated with RNA polymerase, thus regulating the rate of gene expression (Kohler et al., 2017; Demo et al., 2017). In mitochondria, such coupling does not occur because transcription and translation are most likely compartmented.

Where does initiation occur in transcription?

Initiation is the beginning of transcription. It occurs when the enzyme RNA polymerase binds to a region of a gene called the promoter. This signals the DNA to unwind so the enzyme can ”read” the bases in one of the DNA strands. The enzyme is now ready to make a strand of mRNA with a complementary sequence of bases.

Does mRNA interact with mitochondria?

Hence, these data indicate that mRNA targeting to the mitochondrial surface represents an attractive strategy for allowing the mitochondrial import of proteins originally encoded by the mitochondrial genome without any amino acid change in the protein that could interfere with its biologic activity.

Does the mitochondria produce RNA?

Although most DNA is packaged in chromosomes within the nucleus, mitochondria also have a small amount of their own DNA. The remaining genes provide instructions for making molecules called transfer RNA (tRNA) and ribosomal RNA (rRNA), which are chemical cousins of DNA.

Do mitochondria replicate themselves?

Mitochondria are self-replicating organelles that occur in various numbers, shapes, and sizes in the cytoplasm of all eukaryotic cells. Mitochondria contain their own genome that is separate and distinct from the nuclear genome of a cell.

What is mitochondrial transcription?

Mitochondrial transcription is central to gene expression and is also intimately associated with replication and mitochondrial DNA maintenance. Mitochondrial gene expression is therefore subject to regulation in the nucleus, but local regulation also takes place in the mitochondria.

What is untrue about lysosome?

The following statement about lysosomes IS FALSE: e. Lysosomes synthesize proteins from the recycled amino acids. While lysosomes do break down large protein structures into amino acids which can then be used for the biosynthesis of new proteins, lysosomes do NOT themselves synthesize new proteins from amino acids.

How is mitochondrial DNA transcribed?

Almost the entire mitochondrial genome is transcribed as long polycistronic transcripts. Maturation of the transcripts requires endonucleolytic cleavage, but not all mRNAs are produced through RNase P and RNase Z function. Mitochondrial mRNA steady-state levels are mainly controlled post-transcriptionally.

How is transcription initiated in prokaryotic and eukaryotic cells?

However, initiation of transcription is much more complex in eukaryotes compared to prokaryotes. Unlike the prokaryotic RNA polymerase that can bind to a DNA template on its own, eukaryotes require several other proteins, called transcription factors, to first bind to the promoter region and then help recruit the appropriate polymerase.

What is the origin of mitochondrial transcription?

Mitochondrial transcription Transcription of the mitochondrial genome originates in the major non-coding region containing the L-strand (LSP) and H-strand (HSP) promoters. The light strand promoter controls the transcription of eight of the tRNAs and the MT-ND6gene.

Which transcription factor is required for promoter melting during initiation of transcription?

Posse V. and Gustafsson C.M. (2017) Human mitochondrial transcription factor B2 is required for promoter melting during initiation of transcription. J.

What controls the initiation of translation in mitochondria?

In the mammalian mitochondria, the mitochondrial initiation factors, mtIF2 and mtIF3, control the initiation of translation [102]. During initiation, mtIF3 positions the AUG or AUA initiation codons of the mRNA at the peptidyl (P) site in the mtSSU and prevents the premature association of the mtLSU and mtSSU [103–105].