I have a assignment in my school were i have to explain the expressions trans-gene and cis-gene. I already explained what trans-gene means in my assignment but i don't know about cis-gene. I already looked it up at the Internet and in my biotech-books with no luck. Please help!
10-14-2012, 11:35 PM
(This post was last modified: 06-26-2013, 11:06 PM by Administrator.)
Dear Morten Jarlak,
Here is the detail of Cis-gene:-
First of all let us learn what is Cis. Cis is a Latin word. The meaning of this word will help you to understand the concept of cis-gene. It is very simple. Cis means on the "same side" of. Therefore, Cis-gene is gene (part of DNA or RNA) which regulate (means control) the expression (means function) of genes which are on same DNA (on which cis gene itself is located) and cannot control genes expresion of genes which are on another DNA (which is another concept known as trans gene regulation).
It controls functions of genes of same DNA on which it is located. The best example of this type of gene is lac Operon.
To understand cis gene and before going ahead let us first learn what is operon (best example of cis-gene) ? An operon is a functioning unit of genomic DNA. This contains a cluster of genes which have a single point control.That single point control is called as regulatory signal or promoter. Lac Operon is the best example of Cis-gene. Lac operon is operon (defined above) that is required for transport and metabolism of lactose in bacteria E. coli. This cis genes encode enzymes namely β-galactosidase, lactose permease, and thiogalactoside transacetylase.
These genes are adjacent to each other (hint : means on same part of its own DNA -Cis gene) and has single point control (so called as operon) These are called as lacZ , lac Y and lac A respectively & together constitutes lac operon (Cis-gene).
Cisgenesis is inherited adjustment of vegetation with cisgenes only. A cisgene is a organic gene, coding for an feature, from the crop plant itself or from a intimately suitable donor plant that can be used in traditional reproduction. The gene connected to the conventional breeder’s gene share. A cisgenic plant contains no foreign genetics.
Hey Guys well i think that cisgene is a organic gene, programming for an feature from the plants place itself or from a intimately suitable contributor place that can be used in conventional place reproduction.Thanks!!
There are around number of 22000 protein coding genes in humans. These gens contain information that is extremely critical towards development of an organism and carrying forward a species. Looking at the number of genes one would safely assume that it is not possible for all these genes to be working at the same time. Each gene has a specific function, a specific protein that it produces and therefore specific time duration for functioning. Like in a school full of hundreds of children, a teacher is required to ensure that the students are studying properly; a proper expression regulation mechanism is also needed for genes.
Gene expression regulation is important because it decides which genes will be turned on in which cell and when. These genes when turned on are responsible for proper functioning of a cell. Gene expression regulation is mediated by regulatory elements known as cis regulatory elements and trans regulatory elements.
Cis regulatory elements are DNA sequences that are involved in regulation of gene expression by acting on DNA sequences that are present on the same side as them.
Trans regulatory elements aren’t DNA sequences, but can move through the cytoplasm via diffusion and act on any DNA sequence in the cell. trans regulatory elements are usually associated with DNA sequences coding for proteins.
Cis regulatory elements may be present upstream or downstream of the target sequence and can even be found in the transcription unit. A few examples of cis regulatory elements or cis acting genes are the core promoter in transcription unit, proximal elements, enhancers which bind to activators to ensure maximum efficiency of transcription. Unlike promoters which are present near the target sequence, enhancers are located far away. They act by causing looping of the DNA sequence bringing the transcription factors together.
Another example of a cis gene is the operator gene in lac operon. It when bound by the repressor molecule is unable to initiate transcription. However, when the inducer (lactose) binds to the repressor molecule inactivating it, normal transcription can occur.