perinatal. relating to the period shortly before and after birth; the actual time varies between species. The last 10 to 15% of the pregnancy before parturition to the end of a comparable period after birth would cover present usage of the term. perinatal mortality. the percentage of animals in the danger period which die, as a ratio of the total number exposed.
Normal Gene Tumor Suppressor Gene Is nicknamed the Guardian of the Genome.. Can arrest the cell cycle, trigger apoptosis or senescence, and repair DNA. Chromosome 17 Cell Survival Produces a protein called tumor protein p53, which regulates cell division.
Groups of genes coding for related proteins are arranged in units known as operons. An operon consists of an operator, promoter, regulator, and structural genes. The regulator gene codes for a repressor protein that binds to the operator, obstructing the promoter (thus, transcription) of the structural genes. The regulator does not have to be adjacent to other genes in the operon. If the repressor protein is removed, transcription may occur.