Saccharomyces Cerevisiae- Chromosome VII

In 1996 was released the genome of the yeast Saccharomyces Cerevisiae which was the first eukaryotic organism to be sequenced. It’s composed by sixteen chromosomes and we’ll be focusing on the seventh, having the Saccharomyces Genome Database (SGD) as a reference for our research.

             The chromosome VII has a total length of 1,090,940 bp that can be separated by the   centromere (CEN7) in two arms. The left arm has 496920 bp while the right arm has 593902 bp (figure 1). There are twenty-six ARS (autonomously replicating sequences). The sequence of ARS 706 is shown below (figure 2).

Figure 1- CEN7 (https://www.yeastgenome.org/locus/S000006468)

Figure 2- ARS 706 sequence

         A lot of genes are involved in replication, such as RFC5, SLD3, MCM6, MPT5 and HFM1.

           RFC5 is a DNA binding protein and ATPase that acts as a clamp loader of the proliferating cell nuclear antigen (PCNA) processivity factor for DNA polymerase delta and epsilon.

           SLD3 is involved in the initiation of DNA replication, as well it’s required for proper assembly of replication proteins at the origins of replication.

            MCM6 is a component of the Mcm2-7 hexameric helicase complex that binds chromatin as a part of the pre-replicative complex.

            MPT5 is a mRNA-binding protein. It has broad specificity, recruits the CCR4-NOT deadenylase complex to mRNAs along with Dhh1p and Dcp1p to promote deadenylation, decapping, and decay.

            HFM1 is a meiosis specific DNA helicase. It participates in the conversion of double-stranded breaks to later recombination intermediates, in crossover control and catalyses the unwinding of Holliday junctions.

      References:

1. H Tettelin, et al,1997, The nucleotide sequence of Saccharomyces Cerevisiae chromosome VII, Nature, Volume 387, 81-83;
2. SGD: Saccharomyces Genome Database (https://www.yeastgenome.org).

           Group 2.3: Ana Vale, André Magalhães, Bárbara Alves, Maria Loureiro and Marta Caçador. Biochemistry 2^nd year (2018/2019). University of Minho.